feat: add tested dependency updates with runtime rollback

scripts/update.py

@@ -0,0 +1,10 @@
+#!/usr/bin/env python3
+"""Run with system Python, independently of the application environment."""
+from pathlib import Path
+import sys
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+from jr_einvoice.maintenance import main
+
+if __name__ == '__main__':
+    raise SystemExit(main())