ci: add actionlint workflow

.github/workflows/actionlint.yml

@@ -0,0 +1,23 @@
+name: actionlint
+
+on:
+  push:
+    paths:
+      - .github/workflows/**
+  pull_request:
+    paths:
+      - .github/workflows/**
+
+jobs:
+  actionlint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Download actionlint
+        id: get_actionlint
+        run: bash <(curl https://github.com/raw/rhysd/actionlint/main/scripts/download-actionlint.bash)
+        shell: bash
+      - name: Check workflow files
+        run: ${{ steps.get_actionlint.outputs.executable }} -color
+        shell: bash