feat: add workflow for linting new workflows

.github/workflows/.yamllint

@@ -0,0 +1,7 @@
+---
+extends: default
+
+rules:
+  line-length: disable
+  truthy:
+    check-keys: false

.github/workflows/lint.yml

@@ -0,0 +1,28 @@
+---
+name: Lint
+
+on:
+  push:
+    branches:
+      - 1.x
+  pull_request:
+    branches:
+      - 1.x
+
+defaults:
+  run:
+    # Specify to ensure "pipefail and errexit" are set.
+    # Ref: https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#defaultsrunshell
+    shell: bash
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Lint YAML files
+        working-directory: .github/workflows/
+        run: |
+          yamllint --format github .