pre-commit: add a helper script to check commits individually

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5192>

scripts/check-commits.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+import subprocess
+import sys
+import argparse
+
+def run_pre_commit(start_commit:str):
+    if start_commit == 'HEAD':
+        start_commit = 'HEAD~1'
+    try:
+        subprocess.run(['git', 'rebase', start_commit, '--exec', f"pre-commit run --from-ref HEAD~1 --to-ref HEAD"])
+    except subprocess.CalledProcessError as e:
+        print(f'pre-commit failed with exit code {e.returncode}.')
+        sys.exit(1)
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description="Checks a range of commits one by one with pre-commit.")
+    parser.add_argument('start_commit', nargs='?', default='HEAD~1', type=str,
+                        help='Initial commit (refspec) to start the check.')
+    args = parser.parse_args()
+    run_pre_commit(args.start_commit or 'HEAD~1')