chore(beep boop 🤖): Bump `MCORE_TAG=30ffe88...` (2025-01-05)
🚀 PR to bump `NVIDIA/Megatron-LM` in `Dockerfile.ci` to `MCORE_TAG=30ffe880d15df0d72d5d0cb90707283ce977835d`.  

📝 Please remember the following to-do's before merge: 
- [ ] Verify the presubmit CI  

🙏 Please merge this PR only if the CI workflow completed successfully.