Fixed issue with F# language version because of FSharp.Core version used in Shared for .NET Standard 2.0 target

Author: xperiandri

Directory.Build.targets

@@ -3,6 +3,7 @@
 
   <PropertyGroup>
     <LangVersion>6.0</LangVersion>
+    <FSharpCoreVersion>6.0.*</FSharpCoreVersion>
     <DisableImplicitFSharpCoreReference>true</DisableImplicitFSharpCoreReference>
     <NoWarn>$(NoWarn);NU1504;NU1701</NoWarn>
     <TreatWarningsAsErrors Condition="'$(Configuration)' != 'Debug'">true</TreatWarningsAsErrors>

Packages.props

@@ -8,7 +8,7 @@
   <ItemGroup Label="Common">
     <PackageReference Update="FParsec" Version="1.1.1" />
     <!--<PackageReference Update="FSharp.Core" Version="4.7.2">-->
-    <PackageReference Include="FSharp.Core" Version="6.0.*">
+    <PackageReference Include="FSharp.Core" Version="$(FSharpCoreVersion)">
       <ExcludeAssets>contentFiles</ExcludeAssets>
     </PackageReference>
     <PackageReference Update="Microsoft.Extensions.Http" Version="$(MicrosoftExtensionsVersion)" />

src/FSharp.Data.GraphQL.Shared/FSharp.Data.GraphQL.Shared.fsproj

@@ -29,7 +29,7 @@
 
   <ItemGroup>
     <PackageReference Include="FParsec" />
-    <PackageReference Condition="'$(TargetFramework)' == 'netstandard2.0'" Update="FSharp.Core" VersionOverride="4.7.2" />
+    <PackageReference Condition="'$(TargetFramework)' == 'netstandard2.0'" Update="FSharp.Core" VersionOverride="$(FSharpCoreVersion)" />
   </ItemGroup>
 
   <ItemGroup>