Invitation code is mandatory and Github providers automatic registration not be restricted

[hexf00]

Once the application has invitation codes, users can only sign up for the application with a valid invitation code. Regardless of whether the "Invitation code" signup item is visible or not, users must provide the invitation code during sign up. So, if you want to use invitation codes, you need to add the "Invitation code" signup item to the signup item table.

• invitation-code
• github provider

Expectations:

Invitation codes should limit Github's automatic registration behavior

[casbin-bot]

@tangyang9464 @JalinWang @imp2002