Update Ruleset version to 0.18.0

What does this MR do?

• Update SD Rules version to v0.18.0 to support new rules for SPP
  • Added support for Kubernetes Service Account Token
  • Added support for Hashicorp Vault Service Token
  • Added support for Splunk Authentication Token
  • Added support for GCP Vertex Express Mode Key

What are the relevant issue numbers?

Bump secret-detection-rules to version v0.18.0 ... (gitlab-org/gitlab#576279 - closed)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests updated/added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines