Revert "Bump actions/checkout from 3 to 4"

This reverts commit 9d806d5.

.github/workflows/docs.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
       - name: Build Writerside docs using Docker
         uses: JetBrains/writerside-github-action@v3
       - name: Upload documentation
@@ -92,7 +92,7 @@ jobs:
       image: registry.jetbrains.team/p/writerside/builder/algolia-publisher:2.0.32-2
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v3
       - uses: actions/download-artifact@v4
         with:
           name: algolia-indexes