Update actions/checkout action to v4

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

Author: renovate[bot]

.github/workflows/documentation.yml

@@ -13,7 +13,7 @@ jobs:
     if: github.event_name != 'push'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v1
         with:
           node-version: '12.x'
@@ -25,7 +25,7 @@ jobs:
     if: github.event_name != 'pull_request'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v1
         with:
           node-version: '12.x'