(docs) set budget per model

docs/my-website/docs/proxy/virtual_keys.md

@@ -93,6 +93,7 @@ Request Params:
 - `config`: *Optional[dict]* - any key-specific configs, overrides config in config.yaml
 - `spend`: *Optional[int]* - Amount spent by key. Default is 0. Will be updated by proxy whenever key is used. https://docs.litellm.ai/docs/proxy/virtual_keys#managing-auth---tracking-spend
 - `max_budget`: *Optional[float]* - Specify max budget for a given key.
+- `model_max_budget`: *Optional[dict[str, float]]* - Specify max budget for each model, `model_max_budget={"gpt4": 0.5, "gpt-5": 0.01}`
 - `max_parallel_requests`: *Optional[int]* - Rate limit a user based on the number of parallel requests. Raises 429 error, if user's parallel requests > x.
 - `metadata`: *Optional[dict]* - Metadata for key, store information for key. Example metadata = {"team": "core-infra", "app": "app2", "email": "ishaan@berri.ai" }
 
@@ -676,8 +677,6 @@ general_settings:
 
 ### [BETA] Dynamo DB 
 
-Only live in `v1.16.21.dev1`. 
-
 #### Step 1. Save keys to env
 
 ```shell