[ci] Bump google-github-actions/setup-gcloud from 2 to 3

Bumps [google-github-actions/setup-gcloud](https://github.com/google-github-actions/setup-gcloud) from 2 to 3.
- [Release notes](https://github.com/google-github-actions/setup-gcloud/releases)
- [Changelog](https://github.com/google-github-actions/setup-gcloud/blob/main/CHANGELOG.md)
- [Commits](google-github-actions/setup-gcloud@v2...v3)

---
updated-dependencies:
- dependency-name: google-github-actions/setup-gcloud
  dependency-version: '3'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -58,7 +58,7 @@ jobs:
 
       - name: Set up Cloud SDK
         if: ${{ github.event_name=='push' }}
-        uses: "google-github-actions/setup-gcloud@v2"
+        uses: "google-github-actions/setup-gcloud@v3"
 
       - name: Deploy pages to openwisp.org
         if: ${{ github.event_name=='push' }}