Update Gitleaks from 1.24.0 to 3.3.0

What does this MR do?

Updates Gitleaks from 1.24.0 to 3.3.0 with less modification of the default rules.

Detailed changes

• reason renamed to rule in JSON generated by gitleaks CLI (cf. https://github.com/zricethezav/gitleaks/commit/7bd55e33b504f76fc2aec27f4f479a5fb2606480)
• Dropping entropy with merging into rules: https://github.com/zricethezav/gitleaks/blob/v2.1.0/CHANGELOG.md
  • -e (or --entropy) option dropped
  • [entropy] in gitleaks.toml was replaced with a new [[rule]] with entropies
• User-defined SAST_GITLEAKS_ENTROPY_LEVEL environment variable is deprecated but it has NEVER been made public according to the code search: https://sourcegraph.com/search?q=SAST_GITLEAKS_ENTROPY_LEVEL+repo:%5Egitlab%5C.com/gitlab-org&patternType=regexp
  • gitlab-org/gitlab#12948 (comment 287252726)
• gitleaks.toml rules change

Note: rules are updated in !24 (closed)

What are the relevant issue numbers?

Parts of gitlab-org/gitlab#205172 (closed)

Relates to gitlab-org/gitlab#205171 (closed), gitlab-org/gitlab#12948 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added
• [n/a] Documentation created/updated for GitLab EE, if necessary
• [n/a] Documentation created/updated for this project, if necessary
• [n/a] Documentation reviewed by technical writer or follow-up review issue created
• [n/a] Tests added for this feature/bug
• [n/a] Job definition updated, if necessary
  • [n/a] Auto-DevOps template
  • [n/a] Job definition example
  • [n/a] CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• [n/a] Security reports checked/validated by reviewer