Allow for one-liners in overall pattern

Author: arunkannawadi

.github/workflows/commit-checker.yaml

@@ -71,5 +71,5 @@ jobs:
           excludeTitle: 'true' # optional: this excludes the title of a pull request
           checkAllCommitMessages: 'true' # optional: this checks all commits associated with a pull request
           accessToken: ${{ secrets.GITHUB_TOKEN }} # github access token is only required if checkAllCommitMessages is true
-          pattern: '^(?![A-Z].*\.)[A-Z].{0,49}\r?\n\r?\n(?:.{0,71}\r?\n)*(?:.{0,71}\.)?\r?\n?$'
+          pattern: '^(?![A-Z].*\.)[A-Z].{0,49}(\r?|\r?\n(?:.{0,71}\r?\n)*(?:.{0,71}\.)?\r?\n?)$'
           error: "Something is not right"