Add Microsoft.VisualStudio.Threading.Analyzers to the set of analysers

[Lmooney25]

The current set of analysers do not detect async void methods. The appearance of these methods is generally a mistake, and they create situations that can be difficult to debug, so we should have an analyser to warn about them.

The Microsoft.VisualStudio.Threading.Analyzers NuGet packager provides such as analyzer as well as many more for detecting common mistakes regarding threading and async coding. We should add it to the set of analysers in this package.