Update gitleaks.toml with CircleCI access tokens

What does this MR do?

Add regex expression to identify CircleCI personal api tokens and project api tokens.

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• 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
• [x ] Conforms to the code review guidelines
• [x ] Conforms to the Go guidelines
• Security reports checked/validated by reviewer