Revert to checkout v5.0.0 (CExA-project#983)

Author: tpadioleau

.github/workflows/pages.yaml

@@ -144,7 +144,7 @@ jobs:
         uses: jlumbroso/free-disk-space@54081f138730dfa15788a46383842cd2f914a1be  # v1.3.1
         with: {tool-cache: true, large-packages: false}
       - name: Checkout built branch
-        uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3  # v6.0.0
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8  # v5.0.0
         with:
           submodules: true
       - name: Collect image artifact