Up actions/upload-artifact 3 -> 4 (#8)

Author: DaryaLari

.github/workflows/build.yaml

@@ -26,7 +26,7 @@ jobs:
           type: zip
           filename: docs_${{ env.DATE }}.zip
           directory: build
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: docs_${{ env.DATE }}
           path: build/docs_${{ env.DATE }}.zip