[YOLO] add image repository and usecase field to VLLM env (#1432)

Author: datarobot-harness[bot]

public_dropin_gpu_environments/vllm/env_info.json

@@ -6,5 +6,9 @@
   "label": "v0.8.3+dr.1",
   "environmentVersionId": "68225130c69a2f2230f668b5",
   "environmentVersionDescription": "Update to vllm v0.8.3\nFROM vllm/vllm-openai:v0.8.3",
-  "isPublic": true
+  "isPublic": true,
+  "useCases": [
+    "customModel"
+  ],
+  "imageRepository": "env-gpu-vllm"
 }