Directory.Build.props in root folder with c# and f# projects causes issue

When creating a new Visual Studio solution, I would like to use Directory.Build.props to control the c# version number for all c# projects without having to set them individually.

However, having a mix of c# and f# folders causes a compilation error.

Severity    Code    Description Project File    Line    Suppression State
Error   FS0246  Unrecognized value '8.0' for --langversion use --langversion:? for complete list    FSharpLib   C:\source\solution\FSharpLib\FSC    1   Active

This is the smallest solution to demonstrate the issue. In a real solution there is obviously more projects.

Folder Structure

\solution
\solution\Directory.Build.props
\solution\CSharpLib
\solution\FSharpLib

Directory.Build.props

<Project>
 <PropertyGroup>
   <LangVersion>8.0</LangVersion>
 </PropertyGroup>
</Project>

Project Files (for completeness)

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

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>

</Project>

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

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <Compile Include="Library.fs" />
  </ItemGroup>

</Project>

Is it possible to have c sharp and f sharp projects side by side with a Directory.Build.props in the root folder to only apply to c sharp projects?

Moving the build props to a folder with only csharp projects beneath would work but I don't want to structure things this way - I want related modules alongside each other.