Only compile with net461 in visual studio

osu.Game.Resources/osu.Game.Resources.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net461;netstandard2.0;netcoreapp2.0</TargetFrameworks>
+    <TargetFramework Condition="'$(BuildingInsideVisualStudio)' == 'true'">net461</TargetFramework>
+    <TargetFrameworks Condition="'$(BuildingInsideVisualStudio)' != 'true'">net461;netstandard2.0;netcoreapp2.0</TargetFrameworks>
     <Title>osu!ui</Title>
     <Product>osu!ui</Product>
     <Company>ppy Pty Ltd</Company>