Update actions/checkout action to v4 (#27)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/ftp_deploy.yml

@@ -9,7 +9,7 @@ jobs:
   deployment:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 10
       - name: Set up Git-FTP