chore(deps): update actions/upload-pages-artifact action to v4

Author: renovate[bot]

.github/workflows/mkdocs.yaml

@@ -40,7 +40,7 @@ jobs:
           cache: pip
           cache-dependency-path: requirements-docs.txt
       - run: make docs
-      - uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3
+      - uses: actions/upload-pages-artifact@7b1f4a764d45c48632c6b24a0339c27f5614fb0b # v4
         with:
           path: site/