chore(deps): bump github.com/sigstore/cosign/v2 from 2.5.3 to 2.6.0 (#4195)

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

Author: dependabot[bot]