[IMPORTANT] Handle OAuth App access restrictions

[leo]

release currently doesn't work when freshly set up, because GitHub added OAuth access restrictions.

If you install release fresh and try to use it with a GitHub organization, for example, it will render this error:

♥ directory (main) release -P
Error! Could not determine GitHub repository.

When logging the internal error that's causing this, it shows additional details:

Although you appear to have the correct authorization credentials, the `something` organization
has enabled OAuth App access restrictions, meaning that data access to third-parties is limited.
For more information on these restrictions, including how to enable this app,
visit https://docs.github.com/articles/restricting-access-to-your-organization-s-data/

That means, in order for release to work in the first place, it now has to support this scenario. Either by changing the way it authenticates, or by at the very least (as an immediate solution, before the real one gets implemented) rendering a special error in that case and linking to this documentation page that GitHub provides.