chore(github-actions): configure commitlint to lint the PR title (#1060)

* configure commitlint to lint the PR title

* docs(components): update CONTRIBUTING.md

* chore(components): remove changelog preview

* chore(components): remove obsolete commands

Author: fhennig

.github/workflows/changelog-preview.yml

@@ -5,7 +5,7 @@ on:
 
 jobs:
   commitlint:
-    name: Lint commit messages
+    name: Lint PR title format
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
@@ -24,5 +24,8 @@ jobs:
       - name: Install npm packages
         run: npm ci
 
-      - name: Validate PR commits with commitlint
-        run: npx commitlint --from ${{ github.event.pull_request.base.sha }} --verbose
+      - name: Lint PR title
+        env:
+          PR_TITLE: ${{ github.event.pull_request.title }}
+        run: |
+            echo "$PR_TITLE" | npx commitlint --verbose

.github/workflows/commitlint.yml

@@ -16,6 +16,8 @@ commit messages should follow the Conventional Commits specification.
   If you don't mean for a `feat` or `fix` commit to show up in the components change list,
   then you must not edit files in `components/` in the same commit.
 
+We squash-merge PRs, so only the PR title needs to follow this format.
+
 ### Testing The Generated Changelog
 
 To test the generated changelog, run

CONTRIBUTING.md

@@ -11,8 +11,6 @@
     "release-please": "^17.1.2"
   },
   "scripts": {
-    "commitlint:last-commit": "commitlint --from=HEAD~1 --verbose",
-    "commitlint:merge-base": "commitlint --from=$(git merge-base HEAD main) --verbose",
     "release-please-dry-run": "release-please release-pr --dry-run --config-file=components/release-please-config.json --manifest-file=components/.release-please-manifest.json --repo-url='https://github.com/GenSpectrum/dashboard-components' --path components",
     "release-please-changelog-preview": ".github/scripts/preview-changelog.sh"
   }