Is your feature request related to a problem? Please describe.
Cirrus-CI is a hosted CI service used by a number of projects including Ruby, Rust, FreeBSD, PostgreSQL, and curl.
https://cirrus-ci.org/

Describe the solution you'd like
Scorecard should include Cirrus-CI in the list of known CIs (currently documented as appveyor, buildkite, circleci, e2e, github-actions, jenkins, mergeable, test, travis-ci)

Describe alternatives you've considered
None

Additional context
None