Switch to netcoreapp3.1 for tests (#823)

Author: jbevain

Directory.Build.props

@@ -7,7 +7,7 @@
     <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)\cecil.snk</AssemblyOriginatorKeyFile>
-    <DefineConstants Condition=" '$(TargetFramework)' == 'netstandard2.0' OR '$(TargetFramework)' == 'netcoreapp2.1' ">$(DefineConstants);NET_CORE</DefineConstants>
+    <DefineConstants Condition=" '$(TargetFramework)' == 'netstandard2.0' OR '$(TargetFramework)' == 'netcoreapp3.1' ">$(DefineConstants);NET_CORE</DefineConstants>
     <RootNamespace></RootNamespace>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(TargetFramework)' == 'net40' ">

Test/Mono.Cecil.Tests.csproj

@@ -1,9 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
-  <ItemGroup Condition=" '$(TargetFramework)' == 'netcoreapp2.1' ">
+  <ItemGroup Condition=" '$(TargetFramework)' == 'netcoreapp3.1' ">
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp">
       <Version>2.10.0</Version>
     </PackageReference>

rocks/Test/Mono.Cecil.Rocks.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\Mono.Cecil.csproj">

symbols/mdb/Test/Mono.Cecil.Mdb.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\..\..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\Mono.Cecil.csproj">

symbols/pdb/Test/Mono.Cecil.Pdb.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\..\..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\Mono.Cecil.csproj">