build(deps): bump docker/setup-buildx-action from 2 to 3 (#3137)

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](https://github.com/docker/setup-buildx-action/compare/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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build-container.yml

@@ -25,7 +25,7 @@ jobs:
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@v3
       - name: Log in to the Container registry
         uses: docker/login-action@3d58c274f17dffee475a5520cbe67f0a882c4dbb
         if: ${{ github.repository_owner == 'freifunk-gluon' && github.event_name == 'push' }}