Update docker/setup-buildx-action action to v3 (#56)

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

.github/workflows/docker-img.yml

@@ -21,7 +21,7 @@ jobs:
 
       - name: Set up Docker Buildx
         id: buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@v3
 
       - name: Log-in to ghcr.io
         run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login https://ghcr.io -u ${{ github.actor }} --password-stdin