docs(openapi): Update docstring's default openapi version

Signed-off-by: victorperezpiqueras <47613476+victorperezpiqueras@users.noreply.github.com>

Author: victorperezpiqueras

aws_lambda_powertools/event_handler/openapi/config.py

@@ -32,7 +32,7 @@ class OpenAPIConfig:
         The title of the application.
     version: str
         The version of the OpenAPI document (which is distinct from the OpenAPI Specification version or the API
-    openapi_version: str, default = "3.0.0"
+    openapi_version: str, default = "3.1.0"
         The version of the OpenAPI Specification (which the document uses).
     summary: str, optional
         A short summary of what the application does.