Update version in appveyor.yml

Merge pull request PowerShell#231 from PowerShell/release/0.6.1

Prepare 0.6.1 release

Merge pull request PowerShell#219 from PowerShell/release/0.6.0

Prepare 0.6.0 release

Merge pull request PowerShell#188 from PowerShell/release/0.5.0

Release 0.5.0

Bump version to 0.4.3, update changelog

Merge pull request PowerShell#162 from PowerShell/release/0.4.2

Prepare version 0.4.2 for release

Bump version to 0.4.1

Merge pull request PowerShell#145 from PowerShell/release/0.4.0

Release 0.4.0

Releasing current 0.2.0 binaries before NuGet publishing begins