chore(deps): bump sigstore/cosign-installer from 3.6.0 to 3.8.0 (#3825)

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 3.6.0 to 3.8.0.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@4959ce0...c56c2d3)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/docker.yml

@@ -66,7 +66,7 @@ jobs:
             ${{ runner.os }}-buildx-
 
       - name: Install Cosign
-        uses: sigstore/cosign-installer@4959ce089c160fddf62f7b42464195ba1a56d382
+        uses: sigstore/cosign-installer@c56c2d3e59e4281cc41dea2217323ba5694b171e
 
       - name: Login Docker Hub
         uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567