chore(deps): bump sigstore/cosign-installer in the ci-dependencies group (#2028)

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


Updates `sigstore/cosign-installer` from 3.8.2 to 3.9.1
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](https://github.com/sigstore/cosign-installer/compare/v3.8.2...v3.9.1)

---
updated-dependencies:
- dependency-name: sigstore/cosign-installer
  dependency-version: 3.9.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: ci-dependencies
...

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