THRIFT-4990 Upgrade to .NET Core 3.1 (LTS)
Client: netstd
Patch: Jens Geyer

This closes #1961
diff --git a/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj b/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
index b060182..20fdfe4 100644
--- a/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
+++ b/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
@@ -18,14 +18,14 @@
     under the License.
   -->
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.0</TargetFramework>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="CompareNETObjects" Version="4.58.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="1.4.0" />
-    <PackageReference Include="MSTest.TestFramework" Version="1.4.0" />
-    <PackageReference Include="NSubstitute" Version="4.0.0" />
+    <PackageReference Include="CompareNETObjects" Version="4.64.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="2.0.0" />
+    <PackageReference Include="MSTest.TestFramework" Version="2.0.0" />
+    <PackageReference Include="NSubstitute" Version="4.2.1" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\Thrift\Thrift.csproj" />