Migrate defining version to use hatch-vcs

Author: ketozhang

asdf_pydantic/__version__.py

@@ -1,5 +1,5 @@
 [build-system]
-requires = ["hatchling"]
+requires = ["hatchling", "hatch-vcs"]
 build-backend = "hatchling.build"
 
 [project]
@@ -37,7 +37,7 @@ Source = "https://github.com/ketozhang/asdf-pydantic"
 'asdf.extensions' = { asdf_pydantic_extension = 'asdf_pydantic.examples.extensions:get_extensions' }
 
 [tool.hatch.version]
-path = "asdf_pydantic/__version__.py"
+source = "vcs"
 
 # Default Environment
 [tool.hatch.envs.default]