Invite Github users to Hasura Cloud

### Is your proposal related to a problem?

No

### Describe the solution you'd like

I want to be able to invite Github users to collaborate with me on a Hasura Cloud project as opposed to just via email address

The issue does not identify files, tests, or entry points. Start by locating the Hasura Cloud project invitation flow and its existing email-based collaboration path; done should mean that a project owner can invite a GitHub user to collaborate instead of relying only on an email address.

Written by the indexing model from the issue text.