[StepSecurity] ci: Harden GitHub Actions (#114)

Signed-off-by: StepSecurity Bot <bot@stepsecurity.io>

.github/workflows/pr.yml

@@ -6,13 +6,21 @@ on:
   pull_request:
     branches: [main]
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - name: Harden Runner
+        uses: step-security/harden-runner@91182cccc01eb5e619899d80e4e971d6181294a7 # v2.10.1
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - name: Setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@0a44ba7841725637a19e28fa30b79a866c81b0a6 # v4.0.4
         with:
           node-version-file: '.nvmrc'
       - name: Install dependencies