Actions: Reject GH secrets (#105289)

.github/workflows/reject-gh-secrets.yml

@@ -0,0 +1,31 @@
+name: Reject GitHub secrets
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+  push:
+    branches:
+      - main
+      - release-*
+
+permissions: {}
+
+jobs:
+  reject-gh-secrets:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+        with:
+          persist-credentials: false
+
+      - name: Grep for secrets accesses
+        run: |
+          if grep -E '\$\{\{\s*secrets\s*\.\s*[a-zA-Z0-9_\-]+\s*\}\}' .github/workflows/*.yml | grep -vF 'secrets.GITHUB_TOKEN' | grep -vF '# nolint:reject-gh-secrets'; then
+            echo "Found secrets access in the codebase. Please remove it in favour of Vault secrets."
+            echo "If you are sure this is correct, add '# nolint:reject-gh-secrets' to the end of the line. Be VERY careful with this."
+            exit 1
+          fi