Fix up test project references

Author: Redth

tests/AndroidSupport.Tests/AndroidSupport.Tests.csproj

@@ -125,21 +125,6 @@
     <Reference Include="Xamarin.Android.Support.v7.CardView">
       <HintPath>..\..\output\Xamarin.Android.Support.v7.CardView.dll</HintPath>
     </Reference>
-    <Reference Include="xunit.abstractions">
-      <HintPath>..\packages\xunit.abstractions.2.0.1\lib\netstandard1.0\xunit.abstractions.dll</HintPath>
-    </Reference>
-    <Reference Include="xunit.assert">
-      <HintPath>..\packages\xunit.assert.2.2.0\lib\netstandard1.1\xunit.assert.dll</HintPath>
-    </Reference>
-    <Reference Include="xunit.core">
-      <HintPath>..\packages\xunit.extensibility.core.2.2.0\lib\netstandard1.1\xunit.core.dll</HintPath>
-    </Reference>
-    <Reference Include="xunit.execution.dotnet">
-      <HintPath>..\packages\xunit.extensibility.execution.2.2.0\lib\netstandard1.1\xunit.execution.dotnet.dll</HintPath>
-    </Reference>
-    <Reference Include="xunit.runner.utility.netstandard15">
-      <HintPath>..\packages\xunit.runner.utility.2.2.0\lib\netstandard1.5\xunit.runner.utility.netstandard15.dll</HintPath>
-    </Reference>
     <Reference Include="Xamarin.Android.Support.v7.RecyclerView">
       <HintPath>..\..\output\Xamarin.Android.Support.v7.RecyclerView.dll</HintPath>
     </Reference>
@@ -162,6 +147,13 @@
 		  <HintPath>..\..\output\Xamarin.Android.Arch.Lifecycle.Runtime.dll</HintPath>
 		</Reference>
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="xunit.core" Version="2.3.1" />
+    <PackageReference Include="xunit.abstractions" Version="2.0.1" />
+    <PackageReference Include="xunit.assert" Version="2.3.1" />
+    <PackageReference Include="xunit.extensibility.execution" Version="2.3.1" />
+    <PackageReference Include="xunit.runner.utility" Version="2.3.1" />
+  </ItemGroup>
   <ItemGroup>
     <Compile Include="MainActivity.cs" />
     <Compile Include="Resources\Resource.designer.cs" />
@@ -171,8 +163,6 @@
   <ItemGroup>
     <None Include="Resources\AboutResources.txt" />
     <None Include="Properties\AndroidManifest.xml" />
-    <None Include="Assets\AboutAssets.txt" />
-    <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
     <AndroidResource Include="Resources\layout\Main.axml" />