deps: update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/docusaurus-deploy.yml

@@ -10,7 +10,7 @@ jobs:
     name: Docusaurus Build
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v3
         with:
           node-version: 18

.github/workflows/docusaurus-test.yml

@@ -10,7 +10,7 @@ jobs:
     name: Docusaurus Test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v3
         with:
           node-version: 18