Fix zizmor issues

Author: pquentin

.github/workflows/validate-pr.yml

@@ -10,6 +10,10 @@ on:
       - main
       - '[0-9]+.[0-9]+'
 
+permissions:
+  contents: read          # To checkout repositories
+  pull-requests: write    # To create/update PR comments
+
 jobs:
   validate-apis:
     name: build
@@ -23,13 +27,15 @@ jobs:
       - uses: actions/checkout@v4
         with:
           path: ./elasticsearch-specification
+          persist-credentials: false
 
       - uses: actions/checkout@v4
         with:
           repository: elastic/clients-flight-recorder
           path: ./clients-flight-recorder
           token: ${{ secrets.PAT }}
           ref: ${{ github.base_ref }}
+          persist-credentials: false
 
       - name: Use Node.js 22
         uses: actions/setup-node@v4