v2.2.0-alpha

See https://github.com/natemcmaster/CommandLineUtils/blob/master/CHANGELOG.md for release notes.

Build: https://ci.appveyor.com/project/natemcmaster/commandlineutils/build/2.2.0-alpha
Release: https://www.nuget.org/packages/McMaster.Extensions.CommandLineUtils/2.2.0-alpha