ci: lint PR title instead of commits

.github/workflows/commitlint.yml

@@ -4,6 +4,7 @@ on:
   pull_request:
     types:
       - opened
+      - edited
       - reopened
       - synchronize
       - ready_for_review
@@ -29,5 +30,7 @@ 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

CONTRIBUTING.md

@@ -4,7 +4,9 @@ Contributions are very welcome! Just fork the repository, develop in a branch an
 
 ## Commit Messages
 
-We follow [conventional commits](https://www.conventionalcommits.org) when writing commit messages.
+Commits on the `main` branch should follow [conventional commits](https://www.conventionalcommits.org).
+Since we squash-merge pull requests, the PR title should also follow conventional commits
+(because it will become the commit message of the squashed commit).
 The messages themselves should help future developers understand **why** changes were made.
 
 ## Code Style

package.json

@@ -8,9 +8,5 @@
     "@commitlint/cli": "^19.4.0",
     "@commitlint/config-conventional": "^19.2.2",
     "@commitlint/types": "^19.0.3"
-  },
-  "scripts": {
-    "commitlint:last-commit": "commitlint --from=HEAD~1 --verbose",
-    "commitlint:merge-base": "commitlint --from=$(git merge-base HEAD main) --verbose"
   }
 }