chore(deps): update actions/checkout action to v4.2.1

Author: renovate[bot]

.github/workflows/update-readme.yml

@@ -9,7 +9,7 @@ jobs:
   sync-assets:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4.1.7
+      - uses: actions/checkout@v4.2.1
         with:
           fetch-depth: 0