ci: add zizmor workflow and pin all GitHub Actions to SHA hashes (#5237)

.github/workflows/zizmor.yml

@@ -0,0 +1,27 @@
+name: zizmor
+on:
+  push:
+    branches: [main]
+    paths:
+      - '.github/workflows/**'
+  pull_request:
+    branches: [main]
+    paths:
+      - '.github/workflows/**'
+jobs:
+  zizmor:
+    name: Audit GitHub Actions
+    runs-on: ubuntu-latest
+    permissions:
+      security-events: write
+      contents: read
+      actions: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
+      - name: Run zizmor
+        uses: zizmorcore/zizmor-action@71321a20a9ded102f6e9ce5718a2fcec2c4f70d8 # v0.5.2
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}