Re-add checkout step, but remove persist-credentials

Author: goldenapples

.github/workflows/build-release-branch.yml

@@ -14,6 +14,11 @@ jobs:
     name: "Update release branch"
     runs-on: ubuntu-latest
     steps:
+      - name: Check out project
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
+
       - name: Set up Node
         uses: actions/setup-node@v4
         with: