Refactor version management to use dedicated version module

src/annotated_doc/__init__.py

@@ -1,5 +1,4 @@
-from importlib.metadata import version
-
+from .version import VERSION
 from .main import Doc as Doc
 
-__version__ = version("annotated-doc")
+__version__ = VERSION

src/annotated_doc/version.py

@@ -0,0 +1,22 @@
+from importlib.metadata import metadata
+
+
+NAME = 'annotated-doc'
+"""Package name."""
+
+try:
+    pkg_data = metadata(NAME)
+except Exception:
+    pkg_data = {}
+
+VERSION = pkg_data.get('Version')
+"""Package version."""
+
+AUTHOR = pkg_data.get('Author')
+"""Package author."""
+
+AUTHOR_EMAIL = pkg_data.get('Author-email')
+"""Package author e-mail."""
+
+LICENSE = pkg_data.get('License')
+"""Package license."""