Bump sigstore/cosign-installer in the github-actions group (#159)

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


Updates `sigstore/cosign-installer` from 3.9.0 to 3.9.1
- [Release notes](https://github.com/sigstore/cosign-installer/releases)
- [Commits](https://github.com/sigstore/cosign-installer/compare/v3.9.0...v3.9.1

)

---
updated-dependencies:
- dependency-name: sigstore/cosign-installer
  dependency-version: 3.9.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: github-actions
...

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