Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/deploy_doc.yml

@@ -12,7 +12,7 @@ jobs:
   deploy_doc:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Deploy
         if: github.event_name != 'pull_request'
         uses: JamesIves/[email protected]