security/rubygem-gitlab-secret_detection: update to 0.42.0
Required for gitlab 19.1.0
Changes: https://gitlab.com/gitlab-org/security-products/secret-detection/secret-detection-service/-/blob/main/CHANGELOG.md
(cherry picked from commit 19b082d4e0417c2f56f0f0ae45f6a30838b1b194)