Support GitHub Enterprise Self-hosted when logging in with Okta

[drazisil-codecov]

When the "Login with Okta" feature was designed, it was only configured to work with GitHub Enterprise Cloud, which lives at github.com.

Therefore , in order to support GitHub Enterprise Self-hosted, it would need additional functionality to be able to auth and API against custom domains.

This is a request from current self hosted customer, but they will need this support when they migrate to Codecov Dedicated Cloud as well.

[jerrodcodecov]

@scott-codecov @nicholas-codecov is there a conversation happening somewhere on this matter?

[eliatcodecov]

This is being tracked here: codecov/engineering-team#910

[jerrodcodecov]

Thanks, assigned to next sprint, main customer requesting this has a work around (leaving Github Enterprise login turned on), but is a blocker for a wider rollout.