build(deps): Bump docker/build-push-action from 3 to 6

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 3 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v3...v6)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/tendermint-docker.yml

@@ -50,7 +50,7 @@ jobs:
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Publish to Docker Hub
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: ./DOCKER/Dockerfile

.github/workflows/testapp-docker.yml

@@ -51,7 +51,7 @@ jobs:
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Publish to Docker Hub
-        uses: docker/build-push-action@v3.2.0
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: ./test/e2e/docker/Dockerfile