ci: integrate pr-title-lint into ci

Author: casibbald

.github/workflows/lint-pr.yaml .github/workflows/archive/lint-pr.yaml.github/workflows/lint-pr.yaml renamed to .github/workflows/archive/lint-pr.yaml

@@ -1,8 +1,10 @@
 # CI: proto and commitlint; fan-out Go (fmt, lint, unit-tests) || UI (ui-lint, ui-test);
 # then build (gitops, gitops-server). On tag: image, chart, goreleaser.
 #
-# Flow: conventional-commits (if !tag) -> proto (make proto, git diff) in parallel with
-#   ui-lint, ui-test. Then go-fmt, go-lint, go-unit-tests (need proto). Then build
+# Flow: pr-title-lint (if PR; else skipped) -> conventional-commits (if !tag;
+#   runs when pr-title-lint success or skipped) -> proto (make proto, git diff)
+#   in parallel with ui-lint, ui-test. Then go-fmt,
+#   go-lint, go-unit-tests (need proto). Then build
 #   (make gitops, make gitops-server). Tag jobs (image, chart, goreleaser) need build.
 # No make clean (each run is a fresh checkout).
 #
@@ -31,10 +33,49 @@ env:
   PYTHON_VERSION: "3.12"
 
 jobs:
+  pr-title-lint:
+    name: Validate PR title
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    permissions:
+      pull-requests: write
+    steps:
+      - uses: amannn/action-semantic-pull-request@48f256284bd46cdaab1048c3721360e808335d50 # v6.1.1
+        id: lint_pr_title
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: marocchino/sticky-pull-request-comment@773744901bac0e8cbb5a0dc842800d45e9b2b405 # v2.9.4
+        if: always() && (steps.lint_pr_title.outputs.error_message != null)
+        with:
+          header: pr-title-lint-error
+          message: |
+            Hey there and thank you for opening this pull request! :wave:
+
+            We require pull request titles to follow the
+            [Conventional Commits specification](https://www.conventionalcommits.org/en/v1.0.0/)
+            and it looks like your proposed title needs to be adjusted.
+
+            We use the pull request title in automated release changelog updates, and would like our
+            changelogs to look nice.
+
+            Details:
+
+            ```
+            ${{ steps.lint_pr_title.outputs.error_message }}
+            ```
+
+      - if: ${{ steps.lint_pr_title.outputs.error_message == null }}
+        uses: marocchino/sticky-pull-request-comment@773744901bac0e8cbb5a0dc842800d45e9b2b405 # v2.9.4
+        with:
+          header: pr-title-lint-error
+          delete: true
+
   conventional-commits:
     name: Conventional Commits
+    needs: [pr-title-lint]
     runs-on: ubuntu-latest
-    if: "!startsWith(github.ref, 'refs/tags/')"
+    if: always() && (needs.pr-title-lint.result == 'success' || needs.pr-title-lint.result == 'skipped') && !startsWith(github.ref, 'refs/tags/')
     steps:
       - uses: actions/checkout@v4
         with:

.github/workflows/ci.yaml

@@ -170,7 +170,7 @@ exports[`Footer snapshots default 1`] = `
       class="c3"
     >
       © 
-      2025
+      2026
        Weaveworks
     </span>
   </div>
@@ -347,7 +347,7 @@ exports[`Footer snapshots no api version 1`] = `
       class="c3"
     >
       © 
-      2025
+      2026
        Weaveworks
     </span>
   </div>