build(deps): bump github.com/sigstore/cosign/v2

Bumps the go_modules group with 1 update in the / directory: [github.com/sigstore/cosign/v2](https://github.com/sigstore/cosign).


Updates `github.com/sigstore/cosign/v2` from 2.5.0 to 2.6.2
- [Release notes](https://github.com/sigstore/cosign/releases)
- [Changelog](https://github.com/sigstore/cosign/blob/main/CHANGELOG.md)
- [Commits](sigstore/cosign@v2.5.0...v2.6.2)

---
updated-dependencies:
- dependency-name: github.com/sigstore/cosign/v2
  dependency-version: 2.6.2
  dependency-type: indirect
  dependency-group: go_modules
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]