bump version for new nuget package build with netstandard2.0

[Spacefish]

Hello,

please build a new nuget package and upload it to NuGet.org with netstandard2.0 compatibility.. the current 0.3.3 package has only net40.. Alternatively give me acces to the package in NuGet.org (Spacefish) and i will build and upload it for you :)