Add Support EF6 .NET Standard 2.1

Add Support EF6 .NET Standard 2.1

Author: JonathanMagnan

src/EntityFramework.DynamicLinq/EntityFramework.DynamicLinq.csproj

@@ -3,7 +3,7 @@
         <Description>Dynamic Linq extensions for EntityFramework which adds Async support</Description>
         <AssemblyTitle>EntityFramework.DynamicLinq</AssemblyTitle>
         <Authors>ZZZ Projects;Stef Heyenrath</Authors>
-        <TargetFrameworks>net45;net46</TargetFrameworks>
+        <TargetFrameworks>net45;net46;netstandard2.1</TargetFrameworks>
         <DefineConstants>EF;EFDYNAMICFUNCTIONS</DefineConstants>
         <GenerateDocumentationFile>true</GenerateDocumentationFile>
         <AssemblyName>EntityFramework.DynamicLinq</AssemblyName>
@@ -48,9 +48,13 @@
         <PackageReference Include="JetBrains.Annotations" Version="10.2.1" PrivateAssets="All" />
         <PackageReference Include="EntityFramework" Version="6.1.3" />
     </ItemGroup>
-
+	
     <!--<ItemGroup Condition=" '$(TargetFramework)' == 'net45' ">
         <Reference Include="System" />
         <Reference Include="Microsoft.CSharp" />
     </ItemGroup>-->
+	
+    <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.1'">
+        <PackageReference Include="EntityFramework" Version="6.3.0" />
+    </ItemGroup>
 </Project>