chore(deps): update actions/upload-pages-artifact action to v4 (#25)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/deploy.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Build mkdocs
         run: mkdocs build
       - name: Upload GitHub Pages artifact
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@v4
         with:
           name: site
           path: site/