Source: https://montemagno.com/how-to-convert-a-pcl-library-to-net-standard-and-keep-git-history/
- Unload your PCL project (right click -> unload), and start editing it (right -> click edit)
- Delete Everything in the csproj and insert this:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netstandard2.0</TargetFramework>