fix: Fix a typo in README.md (#1084)

Mike Steinert created 

The environment variable indicated to configure the Azure AI endpoint
did not match the value in [Catwalk][].

[Catwalk]: https://github.com/charmbracelet/catwalk/blob/9d9a86e3a4aec20b8874175c115a3533d5083b54/internal/providers/configs/azure.json#L6

Change summary

README.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Detailed changes

README.md 🔗 

@@ -132,7 +132,7 @@ That said, you can also set environment variables for preferred providers.
 | `AWS_ACCESS_KEY_ID`        | AWS Bedrock (Claude)                               |
 | `AWS_SECRET_ACCESS_KEY`    | AWS Bedrock (Claude)                               |
 | `AWS_REGION`               | AWS Bedrock (Claude)                               |
-| `AZURE_OPENAI_ENDPOINT`    | Azure OpenAI models                                |
+| `AZURE_OPENAI_API_ENDPOINT`| Azure OpenAI models                                |
 | `AZURE_OPENAI_API_KEY`     | Azure OpenAI models (optional when using Entra ID) |
 | `AZURE_OPENAI_API_VERSION` | Azure OpenAI models                                |