Merge pull request #39 from wandera/dependabot/github_actions/docker/…

…build-push-action-4

Bump docker/build-push-action from 3 to 4

.github/workflows/test.yml

@@ -34,7 +34,7 @@ jobs:
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v2
     - name: Docker build
-      uses: docker/build-push-action@v3
+      uses: docker/build-push-action@v4
       with:
         context: .
         build-args: |