Bump docker/setup-buildx-action from 2 to 3

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 2 to 3.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](docker/setup-buildx-action@v2...v3)

---
updated-dependencies:
- dependency-name: docker/setup-buildx-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/test-pr.yml

@@ -49,7 +49,7 @@ jobs:
       # Set up buildx for multi platform builds
       - name: Set up Docker Buildx
         id: buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@v3
 
       # Build & Push Dockerfile (test)
       - name: Build & Push ghcr.io/sdr-enthusiasts/docker-acarsdec:test