Fix update-release-branch-fix.py

This change ensures that the the script can handle
commits with no committer in them. This will happen
for some commits that are auto-generated during
PRs.

Author: aeisenberg

.github/update-release-branch.py

@@ -8,6 +8,8 @@
 import datetime
 import os
 
+import inspect
+
 EMPTY_CHANGELOG = """# CodeQL Action and CodeQL Runner Changelog
 
 ## [UNRELEASED]
@@ -122,7 +124,7 @@ def get_commit_difference(repo):
 
 # Is the given commit the automatic merge commit from when merging a PR
 def is_pr_merge_commit(commit):
-  return commit.committer.login == 'web-flow' and len(commit.parents) > 1
+  return commit.committer != None and commit.committer.login == 'web-flow' and len(commit.parents) > 1
 
 # Gets a copy of the commit message that should display nicely
 def get_truncated_commit_message(commit):