pw_presubmit: Ignore svc account commit messages

Change-Id: I15e189ea6b6af313c366e64428b95ac3872dde97
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/112710
Reviewed-by: Wyatt Hepler <hepler@google.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>

pw_presubmit/py/pw_presubmit/pigweed_presubmit.py

@@ -738,6 +738,9 @@ def _valid_capitalization(word: str) -> bool:
 
 def commit_message_format(_: PresubmitContext):
     """Checks that the top commit's message is correctly formatted."""
+    if git_repo.commit_author().endswith('gserviceaccount.com'):
+        return
+
     lines = git_repo.commit_message().splitlines()
 
     # Show limits and current commit message in log.