Merge branch 'master' into master

Author: tosiaki

.github/workflows/ci.yml

@@ -74,7 +74,7 @@ jobs:
           lake exe graph ./import_graph.html
 
       - name: Upload lean artifacts
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: lean-artifacts
           path: |
@@ -133,7 +133,7 @@ jobs:
       - uses: pandoc/actions/setup@v1
 
       - name: Download lean artifacts
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: lean-artifacts
       - name: Copy from artifacts to pages