Bump sigstore/cosign-installer in the ci-dependencies group

Bumps the ci-dependencies group with 1 update: [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer).


Updates `sigstore/cosign-installer` from 3.7.0 to 3.8.0
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@v3.7.0...v3.8.0)

---
updated-dependencies:
- dependency-name: sigstore/cosign-installer
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: ci-dependencies
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/docker-build-push.yaml

@@ -37,7 +37,7 @@ jobs:
             network=host
       - name: Install cosign
         if: github.event_name != 'pull_request'
-        uses: sigstore/cosign-installer@v3.7.0
+        uses: sigstore/cosign-installer@v3.8.0
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v3
         if: github.event_name != 'pull_request'