build with net 6

nukebuild/_build.csproj

@@ -6,8 +6,7 @@
     <IsPackable>False</IsPackable>
     <NoWarn>CS0649;CS0169</NoWarn>
     <NukeTelemetryVersion>1</NukeTelemetryVersion>
-    <TargetFramework>net7.0</TargetFramework>
-    <WarningsAsErrors>false</WarningsAsErrors>
+    <TargetFramework>net6.0</TargetFramework>
   </PropertyGroup>
  
  <Import Project="..\build\JetBrains.dotMemoryUnit.props" />