Create pixart_sigma_xl_512x512.json

inference-cache-config/pixart_sigma_xl_512x512.json

@@ -0,0 +1,5 @@
+{
+    "Jingya/pixart_sigma_pipe_xl_2_512_ms": [
+        {  "task": "pixart", "batch_size": 1, "height": 512, "width": 512, "num_images_per_prompt": 1, "torch_dtype": "bfloat16", "sequence_length": 120 }
+    ]
+}