🌱 Bump sigstore/cosign-installer from 2.7.0 to 2.8.1 (#2402)

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 2.7.0 to 2.8.1.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](ced07f21fb...9becc61764)

---
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/publishimage.yml

@@ -61,7 +61,7 @@ jobs:
             make install
             make scorecard-ko
      - name: Install Cosign
-       uses: sigstore/cosign-installer@ced07f21fb1da67979f539bbc6304c16c0677e76
+       uses: sigstore/cosign-installer@9becc617647dfa20ae7b1151972e9b3a2c338a2b
      - name: Sign image
        run: |
           cosign sign ghcr.io/${{github.repository_owner}}/scorecard/v4:${{ github.sha }}