Small addition to GitHub enterprise detection

[AlexanderLanin]

Currently GitHub ist auto detected by domain github.com.
While you could work forever on a clever heuristic, it does seem safe to make a minimal adjustment and detect github.* as GitHub.
E.g. github.myorganization.com

As far as I can tell this is https://github.com/microsoft/Git-Credential-Manager-Core/blob/c3a543a1352dba953e027f7a92ee4a94b2293a22/src/shared/GitHub/GitHubHostProvider.cs#L63 and https://github.com/microsoft/Git-Credential-Manager-Core/blob/c3a543a1352dba953e027f7a92ee4a94b2293a22/src/shared/GitHub.Tests/GitHubHostProviderTests.cs#L14

[AlexanderLanin]

This is particularly annoying not just because of lack of OAuth in the generic login. But because the generic login is asking for a password which is disabled on GitHub.
Of course this is trivially fixable by config, but it affects too many users in my case. Someone always has trouble setting up a correct config.