Remove net5, seems some of the test adapters and other tooling is having issues.

Author: damianh

src/LittleForker.Tests/LittleForker.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;netcoreapp3.1;net5.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1;netcoreapp3.1</TargetFrameworks>
     <LangVersion>latest</LangVersion>
     <RootNamespace>LittleForker</RootNamespace>
   </PropertyGroup>

src/LittleForker/LittleForker.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp2.1;netcoreapp3.1;net5.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netcoreapp2.1;netcoreapp3.1</TargetFrameworks>
     <DebugType>full</DebugType>
     <Authors>Damian Hickey</Authors>
     <LangVersion>7.2</LangVersion>