Bump sigstore/cosign-installer from 2.7.0 to 2.8.0 (#110)

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 2.7.0 to 2.8.0.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@v2.7.0...v2.8.0)

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

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

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

.github/workflows/build.yaml

@@ -61,7 +61,7 @@ jobs:
         push: ${{ github.event_name != 'pull_request' }}
         tags: ${{ steps.meta.outputs.tags }}
         labels: ${{ steps.meta.outputs.labels }}
-    - uses: sigstore/cosign-installer@v2.7.0
+    - uses: sigstore/cosign-installer@v2.8.0
     - name: cosign
       if: ${{ github.event_name != 'pull_request' }}
       env: