build(deps): bump docker/setup-buildx-action from 2 to 3 (#7595)

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-docker-image.yml

@@ -100,7 +100,7 @@ jobs:
       # Setup Docker Buildx to allow use of docker cache layers from GH
       - name: Set up Docker Buildx
         id: buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@v3
 
       - name: Authenticate to Google Cloud
         id: auth

.github/workflows/zcash-lightwalletd.yml

@@ -105,7 +105,7 @@ jobs:
       # Setup Docker Buildx to allow use of docker cache layers from GH
       - name: Set up Docker Buildx
         id: buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@v3
 
       # Setup gcloud CLI
       - name: Authenticate to Google Cloud