Update docker/setup-buildx-action action to v4

Author: renovate[bot]

.github/workflows/test.yml

@@ -22,7 +22,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v6
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
       - name: Tests of actinia-module-plugin
         id: docker_build
         uses: docker/build-push-action@v6