[changelog skip] Fix Escaping in Changelog Script

The previous PR had a bug where the REGEX for grep was not properly escaped. This PR fixes that issue.

.github/workflows/check_changelog.yml

@@ -9,4 +9,4 @@ jobs:
  - uses: actions/checkout@v1
  - name: Check that CHANGELOG is touched
  run: |
- cat $GITHUB_EVENT_PATH | jq .pull_request.title | grep -i '[((changelog skip)|(ci skip))]' || git diff remotes/origin/${{ github.base_ref }} --name-only | grep CHANGELOG.md
+ cat $GITHUB_EVENT_PATH | jq .pull_request.title | grep -i '\[\(\(changelog skip\)\|\(ci skip\)\)\]' || git diff remotes/origin/${{ github.base_ref }} --name-only | grep CHANGELOG.md