ci: use zizmor and remediate findings

.github/workflows/test.yaml

@@ -8,24 +8,28 @@ on:
     branches:
       - main
 
+permissions: {}
+
 jobs:
   test:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
+        with:
+          persist-credentials: false
       - name: Setup NodeJS
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
         with:
           node-version: 22
       - name: Setup Hugo
-        uses: peaceiris/actions-hugo@v3
+        uses: peaceiris/actions-hugo@2752ce1d29631191ea3f27c23495fa06139a5b78 # v3.2.1
         with:
           # same as netlify.toml
           hugo-version: '0.148.2'
           extended: true
       - name: Set up Python 3.13
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
         with:
           python-version: 3.13
       - name: Setup html5validator

.github/workflows/zizmor.yml

@@ -0,0 +1,36 @@
+name:  Lint GitHub Actions
+
+on:
+  push:
+    branches:
+      - main
+      - release-branch-*
+  pull_request:
+    branches:
+      - '**'
+  workflow_dispatch:
+
+permissions: {}
+
+jobs:
+  zizmor:
+    runs-on: ubuntu-24.04
+
+    env:
+      ZIZMOR_IMAGE: ghcr.io/zizmorcore/zizmor:1.25.2@sha256:14ea7f5cc7c67933394a35b5a38a277397818d232602635edb2010b313afb110
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - name: Run zizmor
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          docker run \
+            --volume "${GITHUB_WORKSPACE}:/src:ro" \
+            --workdir "/src" \
+            --env "GH_TOKEN" \
+            "$ZIZMOR_IMAGE" -- /src