Bump actions/download-artifact from 7 to 8 (#77)

Author: dependabot[bot]

.github/workflows/build.yml

@@ -70,7 +70,7 @@ jobs:
 
       # Fetch the built HTML from the build job
       - name: Download HTML artifact
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: html-${{ github.sha }}
           path: _build/html