fix: Return proper error message instead of raising an exception when the directory doesn't exist for the update command.

Author: dbanty

openapi_python_client/__init__.py

@@ -123,7 +123,7 @@ def update(self) -> Sequence[GeneratorError]:
         """Update an existing project"""
 
         if not self.package_dir.is_dir():
-            raise FileNotFoundError()
+            return [GeneratorError(detail=f"Directory {self.package_dir} not found")]
         print(f"Updating {self.package_name}")
         shutil.rmtree(self.package_dir)
         self._create_package()