Merge pull request #14242 from NixOS/dependabot/github_actions/actions/checkout-5

build(deps): bump actions/checkout from 4 to 5

Author: edolstra

.github/workflows/backport.yml

@@ -20,7 +20,7 @@ jobs:
         with:
           app-id: ${{ vars.CI_APP_ID }}
           private-key: ${{ secrets.CI_APP_PRIVATE_KEY }}
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           # required to find all branches