Bump flawfinder to v4.0.0 for 16.0 release

What does this MR do?

• Bump to next major version
• upgrade gitlab.com/gitlab-org/security-products/analyzers/command/v2 version [v1.10.2 => v2.1.0]
• upgrade gitlab.com/gitlab-org/security-products/analyzers/report/v4 version [v3.22.1 => v4.1.0]

What are the relevant issue numbers?

gitlab-org/gitlab#375364 (closed)

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 added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer