Bump to .NET 6.0.100-preview.3.21202.5 (dotnet#656)

* Android 11.0.200.196
  * Catalyst 14.3.100.471
  * iOS 14.4.100.1326

Bump reunion to stable 0.5 (dotnet#610)

* Bump reunion to stable 0.5

* - remove life cycle apis

Use netstandard2.0 for build tasks (dotnet#496)

* Use netstandard2.0 for build tasks

It seems that Visual Studio's MSBuild doesn't always resolve net6.0 references correctly, so the build tasks built for net6.0 are not working reliably.  There's no reason these cannot be netstandard2.0, so switching them back to build on that TFM for now which should produce working build tasks in IDE's

* Use proper CodeDom

* Include CodeDom in buildTransitive and bump to 4.7

Implement CharacterSpacing property in LabelHandlers (dotnet#463)

* Implement CharacterSpacing property in LabelHandlers

* Add a bunch more tests

* This is needed

Co-authored-by: Matthew Leibowitz <[email protected]>