Use setup.cfg instead of setup.py

docs/conf.py

 # -*- coding: utf-8 -*-
 #
-# Copyright (C) 2020 - 2021 TU Wien.
+# Copyright (C) 2020-2022 TU Wien.
 #
 # Invenio-Config-TUW is free software; you can redistribute it and/or modify
 # it under the terms of the MIT License; see LICENSE file for more details.
 
 """Sphinx configuration."""
 
-import os
-
 import sphinx.environment
 
+from invenio_config_tuw import __version__
+
 # -- General configuration ------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.
@@ -55,24 +55,15 @@ author = "TU Wien"
 #
 # The short X.Y version.
 
-# Get the version string. Cannot be done with import!
-g = {}
-with open(
-    os.path.join(os.path.dirname(__file__), "..", "invenio_config_tuw", "version.py"),
-    "rt",
-) as fp:
-    exec(fp.read(), g)
-    version = g["__version__"]
-
 # The full version, including alpha/beta/rc tags.
-release = version
+release = __version__
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-language = None
+language = "en"
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used: