GH Actions: add actionlint job

.github/workflows/qa.yml

@@ -0,0 +1,37 @@
+name: QA
+
+on:
+  # Run on all pushes and on all pull requests.
+  push:
+  pull_request:
+  # Allow manually triggering the workflow.
+  workflow_dispatch:
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  actionlint:
+    name: 'Check GHA workflows'
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - name: Add problem matcher
+        if: ${{ github.event_name == 'pull_request' }}
+        shell: bash
+        run: |
+          curl -o actionlint-matcher.json https://raw.githubusercontent.com/rhysd/actionlint/main/.github/actionlint-matcher.json
+          echo "::add-matcher::actionlint-matcher.json"
+
+      - name: Check workflow files
+        uses: docker://rhysd/actionlint:latest
+        with:
+          args: -color

.github/workflows/tests.yml

@@ -40,7 +40,7 @@ jobs:
       uses: "ramsey/composer-install@v3"
       with:
         # For PHP "nightly", we need to install with ignore platform reqs as not all dependencies may allow it yet.
-        composer-options: ${{ matrix.php == '8.6' && '--ignore-platform-req=php+' || '' }}
+        composer-options: ${{ matrix.php-versions == '8.6' && '--ignore-platform-req=php+' || '' }}
         # Bust the cache at least once a month - output format: YYYY-MM.
         custom-cache-suffix: $(date -u "+%Y-%m")