Requiring two-factor authentication

[azu]

This guideline that add new member as Owner.
So, maintainer === owner.
Owner Permission levels is highest. It contains security risk.

• Permission levels for an organization - User Documentation

GitHub and npm have beend supported two-factor authentication.

• Securing your account with two-factor authentication (2FA) - User Documentation
• 16 - Using two-factor authentication | npm Documentation

Also, GitHub can Requiring two-factor authentication in your organization.

We need to add new section for security or some tips.

What is name of the section?

[azu]

"Requirement" section?

## Requirement

This organization requre following things.
If you don't want to accept this, you can discuss existing member or deny the invitation.

- [ ] two-factor authentication
- [ ] some ?