nemo2riva of Punctuation_and_Capitalization with NeMo:1.6.0rc0 crashes
I have a prebuilt Punctuation_and_Capitalization model (NeMo:1.4.0). Running nemo2riva with NeMo:1.5.1 performs the conversion as it should, however, running nemo2riva with master branch of NeMo (1.6.0rc0) crashes with the following error
```
INFO: Logging level set to 20                                                                                                                                                                                                                   
INFO: Restoring NeMo model from 'data/nemo/Punctuation_and_Capitalization.nemo'                                                                                                                                                                 
[NeMo I 2022-01-20 15:59:39 common:489] Model instantiation from target class nemo.collections.nlp.models.token_classification.punctuation_capitalization_model.PunctuationCapitalizationModel failed with following error.                     
    Falling back to `cls`.                                                                                                                                                                                                                      
    Traceback (most recent call last):                                                                                                                                                                                                          
      File "/data/NeMo/nemo/core/classes/common.py", line 463, in from_config_dict                                                                                                                                                              
        imported_cls = import_class_by_path(target_cls)                                                                                                                                                                                         
      File "/data/NeMo/nemo/utils/model_utils.py", line 462, in import_class_by_path                                                                                                                                                            
        mod = __import__(path, fromlist=[class_name])                                                                                                                                                                                           
      File "/data/NeMo/nemo/collections/nlp/__init__.py", line 15, in <module>                                                                                                                                                                  
        from nemo.collections.nlp import data, losses, models, modules                                                                                                                                                                          
      File "/data/NeMo/nemo/collections/nlp/models/__init__.py", line 15, in <module>                                                                                                                                                           
        from nemo.collections.nlp.models.dialogue_state_tracking.sgdqa_model import SGDQAModel                                                                                                                                                  
      File "/data/NeMo/nemo/collections/nlp/models/dialogue_state_tracking/__init__.py", line 15, in <module>                                                                                                                                   
        from nemo.collections.nlp.models.dialogue_state_tracking.sgdqa_model import SGDQAModel                                                                                                                                                  
      File "/data/NeMo/nemo/collections/nlp/models/dialogue_state_tracking/sgdqa_model.py", line 33, in <module>                                                                                                                                
        from nemo.collections.nlp.models.nlp_model import NLPModel                                                                                                                                                                              
      File "/data/NeMo/nemo/collections/nlp/models/nlp_model.py", line 29, in <module>                                                                                                                                                          
        from nemo.collections.nlp.modules import BertModule                                                                                                                                                                                     
      File "/data/NeMo/nemo/collections/nlp/modules/__init__.py", line 16, in <module>                                                                                                                                                          
        from nemo.collections.nlp.modules.common import (                                                                                                                                                                                       
      File "/data/NeMo/nemo/collections/nlp/modules/common/__init__.py", line 29, in <module>                                                                                                                                                   
        from nemo.collections.nlp.modules.common.tokenizer_utils import get_tokenizer, get_tokenizer_list                                                                                                                                       
      File "/data/NeMo/nemo/collections/nlp/modules/common/tokenizer_utils.py", line 27, in <module>                                                                                                                                            
        from nemo.collections.nlp.parts.nlp_overrides import HAVE_APEX                                                                                                                                                                          
      File "/data/NeMo/nemo/collections/nlp/parts/nlp_overrides.py", line 33, in <module>                                                                                                                                                       
        from nemo.collections.nlp.modules.common.megatron.module import Float16Module                                                                                                                                                           
      File "/data/NeMo/nemo/collections/nlp/modules/common/megatron/__init__.py", line 15, in <module>                                                                                                                                          
        from nemo.collections.nlp.modules.common.megatron.megatron_bert import MegatronBertEncoder                                                                                                                                              
      File "/data/NeMo/nemo/collections/nlp/modules/common/megatron/megatron_bert.py", line 30, in <module>                                                                                                                                     
        from nemo.collections.nlp.modules.common.megatron.language_model import get_language_model                                                                                                                                              
      File "/data/NeMo/nemo/collections/nlp/modules/common/megatron/language_model.py", line 26, in <module>                                                                                                                                    
        from nemo.collections.nlp.modules.common.megatron.transformer import ParallelTransformer                                                                                                                                                
      File "/data/NeMo/nemo/collections/nlp/modules/common/megatron/transformer.py", line 24, in <module>                                                                                                                                       
        from apex.transformer.utils import divide as safe_divide                                                                                                                                                                                
    ModuleNotFoundError: No module named 'apex.transformer.utils'                                                                                                                                                                               
```
