Merge pull request #40 from dennis6p/fix/open-schema-validation-file-…

…read-only

Open schema validation file in read-only mode

adaptive_cards/validation.py

@@ -513,7 +513,7 @@ def __read_schema_file(self) -> dict[str, Any]:
             Path(__file__)
             .parent.joinpath("schemas")
             .joinpath(f"schema-{self.__schema_version}.json"),
-            "+r",
+            "r",
             encoding="utf-8",
         ) as f:  # pylint: disable=C0103
             return json.load(f)