Nullable 1.3.0

A source code only package which allows you to use .NET's new nullable attributes in older target frameworks like .NET Standard 2.0 or the "old" .NET Framework. This package does not contain any compiled binaries, but instead adds the attribute classes as C# source code to your project. Because this code is compiled together with the rest of your code, the built binaries will not have a dependency on this package, meaning that you can perfectly use it for both libraries and applications. The C# code is only included if you are targeting a framework version which does not support the new nullable attributes. For example, if you create a library which multi-targets .NET Standard 2.0 and 2.1, the majority of the attributes are not included in the .NET Standard 2.1 version, because it already provides these by default. Please see https://github.com/manuelroemer/Nullable for additional information on how to use this package.