Update ServiceStack.Text.Tests.csproj

change nuget.targets to NuGet.targets for linux building

Author: angelcolmenares

tests/ServiceStack.Text.Tests/ServiceStack.Text.Tests.csproj

@@ -344,12 +344,12 @@
     </None>
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <Import Project="$(SolutionDir)\.nuget\nuget.targets" />
+  <Import Project="$(SolutionDir)\.nuget\NuGet.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">
   </Target>
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>