Updated test dependencies

test/Discord.Net.Tests/Discord.Net.Tests.csproj

@@ -17,11 +17,10 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Akavache" Version="5.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0-preview-20170123-02" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0" />
     <PackageReference Include="Newtonsoft.Json" Version="9.0.1" />
-    <PackageReference Include="System.Net.Requests" Version="4.3.0" />
-    <PackageReference Include="xunit" Version="2.2.0-beta5-build3474" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0-beta5-build1225" />
-    <PackageReference Include="xunit.runner.reporters" Version="2.2.0-beta5-build3474" />
+    <PackageReference Include="xunit" Version="2.2.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
+    <PackageReference Include="xunit.runner.reporters" Version="2.2.0" />
   </ItemGroup>
 </Project>