fix(event-handler): set default OpenAPI version to 3.0.0 (#3527)

Co-authored-by: Leandro Damascena <lcdama@amazon.pt>

Author: rubenfonseca

aws_lambda_powertools/event_handler/api_gateway.py

@@ -1375,7 +1375,7 @@ def get_openapi_schema(
             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 = "3.1.0"
+        openapi_version: str, default = "3.0.0"
             The version of the OpenAPI Specification (which the document uses).
         summary: str, optional
             A short summary of what the application does.
@@ -1497,7 +1497,7 @@ def get_openapi_json_schema(
             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 = "3.1.0"
+        openapi_version: str, default = "3.0.0"
             The version of the OpenAPI Specification (which the document uses).
         summary: str, optional
             A short summary of what the application does.
@@ -1567,7 +1567,7 @@ def enable_swagger(
             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 = "3.1.0"
+        openapi_version: str, default = "3.0.0"
             The version of the OpenAPI Specification (which the document uses).
         summary: str, optional
             A short summary of what the application does.

aws_lambda_powertools/event_handler/openapi/models.py

@@ -207,7 +207,7 @@ class Schema(BaseModel):
     readOnly: Optional[bool] = None
     writeOnly: Optional[bool] = None
     examples: Optional[List["Example"]] = None
-    # Ref: OpenAPI 3.1.0: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#schema-object
+    # Ref: OpenAPI 3.0.0: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.0.md#schema-object
     # Schema Object
     discriminator: Optional[Discriminator] = None
     xml: Optional[XML] = None