Update actions/upload-pages-artifact action to v4 (#12)

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

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -107,7 +107,7 @@ jobs:
         run: ./gradlew publishAllPublicationsToMavenCentralRepository --no-configuration-cache
 
       - name: Upload docs
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@v4
         with:
           path: build/dokka/html