Incorrect String Comparison of Username

[jahali25]

duo_universal_csharp/DuoUniversal/Client.cs

Line 152 in 4a5042a

if (idToken.Username != username)

In this line,
if (idToken.Username != username)
it uses the wrong time of string comparison. It does a case-sensitive comparison. However, when you define an alias for a user on the Duo application page, it automatically causes the string to be in lower case. Thus, we should use case-insensitive comparison here. I would replace this line with
if (!string.Equals(idToken.Username, username, StringComparison.InvariantCultureIgnoreCase))
so that different casing doesn't cause an issue since Duo doesn't care about the exact casing for usernames.