added gemini 2.0 models (#8412)

Author: mubashir1osmani

docs/my-website/docs/providers/gemini.md

@@ -688,7 +688,9 @@ response = litellm.completion(
 |-----------------------|--------------------------------------------------------|--------------------------------|
 | gemini-pro            | `completion(model='gemini/gemini-pro', messages)`            | `os.environ['GEMINI_API_KEY']` |
 | gemini-1.5-pro-latest | `completion(model='gemini/gemini-1.5-pro-latest', messages)` | `os.environ['GEMINI_API_KEY']` |
-| gemini-pro-vision     | `completion(model='gemini/gemini-pro-vision', messages)`     | `os.environ['GEMINI_API_KEY']` |
+| gemini-2.0-flash     | `completion(model='gemini/gemini-2.0-flash', messages)`     | `os.environ['GEMINI_API_KEY']` |
+| gemini-2.0-flash-exp     | `completion(model='gemini/gemini-2.0-flash-exp', messages)`     | `os.environ['GEMINI_API_KEY']` |
+| gemini-2.0-flash-lite-preview-02-05	     | `completion(model='gemini/gemini-2.0-flash-lite-preview-02-05', messages)`     | `os.environ['GEMINI_API_KEY']` |