Updated to .NET Core 3.1

Author: FlorianRappl

src/AngleSharp.Js.Tests/AngleSharp.Js.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <RootNamespace>AngleSharp.Js.Tests</RootNamespace>
-    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>Key.snk</AssemblyOriginatorKeyFile>
     <IsPackable>false</IsPackable>
@@ -21,8 +21,8 @@
     <PackageReference Include="AngleSharp.Css" Version="0.14.0" />
     <PackageReference Include="AngleSharp.Xml" Version="0.14.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
-    <PackageReference Include="NUnit" Version="3.13.1" />
+    <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.17.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.4" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.10.0" />
   </ItemGroup>
-</Project>
+</Project>