Appcenter: Add support for build with Xamarin Android 9.4

[toomasz]

Describe the solution you'd like

Add support for Xamarin Android 9.2 as it's released already:
https://github.com/xamarin/xamarin-android/releases/tag/v9.4.0.51

Describe alternatives you've considered
No alternative

Additional context
No context

[nilofer]

Thanks for opening this issue. We're working on getting support for the latest Xamarin.Android at the moment 😁

[toomasz]

@nrajpurkar any ETA? :) I wan't to use it because it has startup tracing feature, which is great.

[nilofer]

We're hoping to get this out in next week's updates to our build machines @toomasz

[jamesmontemagno]

Checkout Boots from @jonathanpeppers https://github.com/jonathanpeppers/boots has the scripts you need there :)

[nilofer]

@toomasz this has been added in. Thanks for your patience in getting this supported!