Bump sigstore/cosign-installer from 2.6.0 to 3.0.2 (#39)

Bumps [sigstore/cosign-installer](https://github.com/sigstore/cosign-installer) from 2.6.0 to 3.0.2.
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](sigstore/cosign-installer@f3c664d...9e9de22)

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

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

.github/workflows/build-and-sign-image.yml

@@ -31,7 +31,7 @@ jobs:
 
       - name: Install cosign
         if: github.event_name != 'pull_request'
-        uses: sigstore/cosign-installer@f3c664df7af409cb4873aa5068053ba9d61a57b6 #v2.6.0
+        uses: sigstore/cosign-installer@9e9de2292db7abb3f51b7f4808d98f0d347a8919 #v3.0.2
         with:
           cosign-release: 'v1.13.1'