cleanup: upgrade package to .NET Core 3.1 or 2.1

Directory.Build.props

@@ -34,7 +34,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <VersionPrefix>1.3.1</VersionPrefix>
+    <VersionPrefix>1.4.0</VersionPrefix>
     <VersionSuffix>beta</VersionSuffix>
     <IncludePreReleaseLabelInPackageVersion Condition="'$(IsStableBuild)' != 'true'">true</IncludePreReleaseLabelInPackageVersion>
     <BuildNumber Condition=" '$(BuildNumber)' == '' ">$([MSBuild]::ValueOrDefault($(BUILD_NUMBER), 0))</BuildNumber>

README.md

@@ -70,7 +70,7 @@ There is nothing special about the name "IPlugin" or the fact that it's an inter
 
 ### The plugins
 
-Typically, it is best to implement plugins by targeting `netcoreapp2.0` or higher. They can target `netstandard2.0` as well, but using `netcoreapp2.0` is better because it reduces the number of redundant System.\* assemblies in the plugin output.
+Typically, it is best to implement plugins by targeting `net5.0` or higher. They can target `netstandard2.0` as well, but using `net5.0` is better because it reduces the number of redundant System.\* assemblies in the plugin output.
 
 A minimal implementation of the plugin could be as simple as this.
 

src/Plugins.Mvc/McMaster.NETCore.Plugins.Mvc.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1</TargetFrameworks>
     <OutputType>library</OutputType>
     <IsPackable>true</IsPackable>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
@@ -21,7 +21,7 @@ See https://github.com/natemcmaster/DotNetCorePlugins/blob/master/README.md for
     <PackageReference Include="Microsoft.AspNetCore.Mvc" Version="2.1.0" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
   </ItemGroup>
 

src/Plugins/McMaster.NETCore.Plugins.csproj

@@ -1,12 +1,12 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1</TargetFrameworks>
     <!--
-      The netcoreapp2.0 API is a subset of the API available in netcoreapp3.0. The public API tool doesn't handle multiple TFMs.
+      The netcoreapp2.1 API is a subset of the API available in netcoreapp3.1. The public API tool doesn't handle multiple TFMs.
       https://github.com/dotnet/roslyn-analyzers/issues/2621
     -->
-    <DisablePublicApiAnalyzer Condition="'$(TargetFramework)' == 'netcoreapp2.0'">true</DisablePublicApiAnalyzer>
+    <DisablePublicApiAnalyzer Condition="'$(TargetFramework)' == 'netcoreapp2.1'">true</DisablePublicApiAnalyzer>
     <OutputType>library</OutputType>
     <IsPackable>true</IsPackable>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
@@ -16,14 +16,14 @@ This package should be used by the host application which needs to load plugins.
 See https://github.com/natemcmaster/DotNetCorePlugins/blob/master/README.md for more samples and documentation.
     </PackageDescription>
     <PackageTags>.NET Core;plugins</PackageTags>
-    <DefineConstants Condition="'$(TargetFramework)' == 'netcoreapp3.0'">$(DefineConstants);FEATURE_UNLOAD</DefineConstants>
-    <DefineConstants Condition="'$(TargetFramework)' == 'netcoreapp3.0'">$(DefineConstants);FEATURE_NATIVE_RESOLVER</DefineConstants>
+    <DefineConstants Condition="'$(TargetFramework)' == 'netcoreapp3.1'">$(DefineConstants);FEATURE_UNLOAD</DefineConstants>
+    <DefineConstants Condition="'$(TargetFramework)' == 'netcoreapp3.1'">$(DefineConstants);FEATURE_NATIVE_RESOLVER</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Microsoft.DotNet.PlatformAbstractions" Version="3.1.6" />
     <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="5.0.0" />
-    <PackageReference Include="System.Text.Json" Version="5.0.1" Condition="'$(TargetFramework)' == 'netcoreapp2.0'" />
+    <PackageReference Include="System.Text.Json" Version="5.0.1" Condition="'$(TargetFramework)' == 'netcoreapp2.1'" />
   </ItemGroup>
 
 </Project>

src/Plugins/PluginLoader.cs

@@ -293,7 +293,7 @@ public Assembly LoadAssembly(string assemblyName)
             return LoadAssembly(new AssemblyName(assemblyName));
         }
 
-#if NETCOREAPP3_0
+#if !NETCOREAPP2_1
         /// <summary>
         /// Sets the scope used by some System.Reflection APIs which might trigger assembly loading.
         /// <para>

test/TestProjects/Banana/Banana.csproj

@@ -5,7 +5,7 @@
   </ItemGroup>
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
   </PropertyGroup>
 
 </Project>

test/TestProjects/DrawingApp/DrawingApp.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

test/TestProjects/Plátano/Plátano.csproj

@@ -5,7 +5,7 @@
   </ItemGroup>
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
   </PropertyGroup>
 
 </Project>