use more predictable version numbers

version.py

@@ -0,0 +1,13 @@
+"""
+SPDX-FileCopyrightText: © Sebastian Thomschke and contributors
+SPDX-License-Identifier: AGPL-3.0-or-later
+SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
+"""
+from datetime import datetime
+import subprocess
+
+
+# used in pyproject.toml [tool.pdm.version]
+def get_version() -> str:
+    commit_hash = subprocess.check_output(['git', 'rev-parse', '--short', 'HEAD']).decode().strip()
+    return f"{datetime.now().year}+{commit_hash}"