chore: remove single-commit-must-match-PR-title validation (#897)

The validateSingleCommit + validateSingleCommitMatchesPrTitle options
force contributors to keep their commit message in sync with the PR
title, which is unnecessary friction — squash-merge already uses the
PR title as the final commit message regardless of individual commit
messages.

Author: notgitika

.github/workflows/pr-title.yml

@@ -38,10 +38,7 @@ jobs:
             The subject "{subject}" found in the pull request title "{title}"
             must start with a lowercase letter.
             Example: "feat: add deploy command"
-          # Validate the commit message when a PR has a single commit, since
-          # GitHub suggests using it as the merge commit message on squash-merge
-          validateSingleCommit: true
-          validateSingleCommitMatchesPrTitle: true
+          validateSingleCommit: false
           # Skip validation for bot/dependency PRs
           ignoreLabels: |
             bot