chore(deps): bump docker/setup-buildx-action from 3 to 4 (#625)

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 3 to 4.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](https://github.com/docker/setup-buildx-action/compare/v3...v4)

---
updated-dependencies:
- dependency-name: docker/setup-buildx-action
  dependency-version: '4'
  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/nightly.yml

@@ -23,7 +23,7 @@ jobs:
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
         with:
           driver: cloud
           endpoint: "meienberger/runtipi-builder"

.github/workflows/release.yml

@@ -55,7 +55,7 @@ jobs:
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
         with:
           driver: cloud
           endpoint: "meienberger/runtipi-builder"