build(deps): Bump docker/setup-buildx-action from 2 to 4

Bumps [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) from 2 to 4.
- [Release notes](https://github.com/docker/setup-buildx-action/releases)
- [Commits](docker/setup-buildx-action@v2...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>

Author: dependabot[bot]

.github/workflows/tendermint-docker.yml

@@ -40,7 +40,7 @@ jobs:
           platforms: all
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@v4
 
       - name: Login to DockerHub
         if: ${{ github.event_name != 'pull_request' }}

.github/workflows/testapp-docker.yml

@@ -41,7 +41,7 @@ jobs:
           platforms: all
 
       - name: Set up Docker Build
-        uses: docker/setup-buildx-action@v2.2.1
+        uses: docker/setup-buildx-action@v4
 
       - name: Login to DockerHub
         if: ${{ github.event_name != 'pull_request' }}