Update docker/setup-buildx-action action to v4

| datasource  | package                    | from   | to     |
| ----------- | -------------------------- | ------ | ------ |
| github-tags | docker/setup-buildx-action | v3.6.1 | v4.0.0 |

Author: renovate[bot]

.github/workflows/tests.yml

@@ -12,7 +12,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3.6.1
+        uses: docker/setup-buildx-action@v4.0.0
 
       - name: Cache Docker layers
         uses: actions/cache@v4.0.2