Moved myget source from .csproj to nuget.config

Author: manfred-brands

nuget.config

@@ -4,5 +4,6 @@
     <clear />
     <!--<add key="Local" value="C:\nuget" />-->
     <add key="nuget" value="https://api.nuget.org/v3/index.json"/>
+    <add key="myget" value="https://www.myget.org/F/nunit/api/v3/index.json"/>
   </packageSources>
-</configuration>
+</configuration>

src/NUnitTestAdapter/NUnit.TestAdapter.csproj

@@ -23,10 +23,6 @@
   </PropertyGroup>
 
   <!-- We reference a specific pre-release version of the nunit.engine -->
-  <PropertyGroup>
-    <RestoreAdditionalProjectSources>https://www.myget.org/F/nunit/api/v3/index.json</RestoreAdditionalProjectSources>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="nunit.engine" Version="4.0.0-dev00100" />
   </ItemGroup>