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

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>

.github/workflows/pull_requests.yml

@@ -53,7 +53,7 @@ jobs:
 
       - name: Set up Docker Buildx
         if: success()
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v4

.github/workflows/releases.yml

@@ -52,7 +52,7 @@ jobs:
           xvfb-run --server-args="-screen 0 1200x800x24" npx grunt testui
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v4