Removed outdated package references.

Author: grokys

test/GitHub.VisualStudio.UnitTests/GitHub.VisualStudio.UnitTests.csproj

@@ -26,7 +26,5 @@
     <PackageReference Include="NSubstitute" Version="2.0.3" />
     <PackageReference Include="NUnit" version="3.9.0" />
     <PackageReference Include="OpenCover" Version="4.6.519" />
-    <PackageReference Include="Rx-Main" Version="2.2.5-custom" targetFramework="net45" />
-    <PackageReference Include="Rx-Testing" Version="2.2.5-custom" targetFramework="net45" />
   </ItemGroup>
 </Project>