Let HttpClient be injected in AuthenticationClient

[senj]

For things like retries, proxies etc. please let us inject HttpClient in AuthenticationClient class

[kvansaders]

Looks like it's already here.

NetCoreForce/src/NetCoreForce.Client/AuthenticationClient.cs

Line 38 in 1fcb398

public AuthenticationClient(string apiVersion = null, HttpClient httpClient = null)