Use actions/checkout@v4

Author: curder

.github/workflows/build-docs.yml

@@ -18,7 +18,7 @@ jobs:
     concurrency:
       group: ${{ github.workflow }}-${{ github.ref }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           # fetch all commits to get last updated time or other git log info
           fetch-depth: 0