Ensure Apple email claim is set for .NET Core 2

[lukefulliton]

Set the ClaimTypes.Email claim from the email claim in the JWT if it is present and an email is not received as a parameter with the sign in.

Resolves #407
This pull-request is the .NET Core 2 version of this pull-request: #411

[lukefulliton]

Looks like there was an issue with the build. I will investigate.

[martincostello]

Looks like there was an issue with the build. I will investigate.

I think there's a few C# 8 features in the code copied verbatim that the older SDK doesn't like.

[lukefulliton]

I think there's a few C# 8 features in the code copied verbatim that the older SDK doesn't like.

Ah, Okay. I'll try recompiling locally with VS 2017

[lukefulliton]

I think there's a few C# 8 features in the code copied verbatim that the older SDK doesn't like.

Yeah, I had downloaded the 2.2.106 SDK and compiled the project solution, but initially did it in VS 2019. LOL :) . The code changes to accommodate the older SDK are now pushed up.

[martincostello]

Great - thanks @lukefulliton! I'll merge this and the other change a bit later on today.

Currently aiming to publish the 3.0.0 and 2.2.1 releases on Monday.

[lukefulliton]

Thanks for all your help @martincostello !