Update coverage script (#437)

* update github action coverage script

* test coverage check

.github/workflows/post-merge.yml

@@ -57,6 +57,6 @@ jobs:
               cp ../ci/coverage_threshold_temp.txt ./ci/coverage_threshold.txt
               git add ./ci/coverage_threshold.txt
               git commit -m "chore: git bot update threshold"
-              git branch -b
+              git branch
               git push origin head:locked_actions_branch
             continue-on-error: true