Specify required LangVersion

[jnyrup]

This project currently requires the consuming project to be using at least C# 12.0 since Reflectify uses C# 12.0 features and is distributed as source.
You might want to specify that requirement somewhere or for maximum compatibility use at most C# 7.3 features, since that's what's a default net47 project uses.

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net47</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Reflectify" Version="1.3.0" />
  </ItemGroup>

</Project>

[dennisdoomen]

Since it's pretty easy to use C# 12 with .NET Framework 4.7, I'd rather go for a documentation update.