Drop net5.0 runtime targets

Where we already had a .NET 6 target, we just drop net5.0. Where .NET 5 was the latest target, we change it to target .NET 6.

This is because .NET 5 is no longer supported by Microsoft, so no one is expected to be using that runtime at this point.

azure-pipelines/build_nonWindows.yml

@@ -13,14 +13,6 @@ steps:
     arguments: --no-build -c $(BuildConfiguration) -f netcoreapp3.1 -v n --settings "$(Build.Repository.LocalPath)/azure-pipelines/$(Agent.OS).runsettings"
     testRunTitle: netcoreapp3.1-$(Agent.JobName)
 
-- task: DotNetCoreCLI@2
-  displayName: Run MessagePack.Tests (net5.0)
-  inputs:
-    command: test
-    projects: tests/MessagePack.Tests/MessagePack.Tests.csproj
-    arguments: --no-build -c $(BuildConfiguration) -f net5.0 -v n --settings "$(Build.Repository.LocalPath)/azure-pipelines/$(Agent.OS).runsettings"
-    testRunTitle: net5.0-$(Agent.JobName)
-
 - task: DotNetCoreCLI@2
   displayName: Run MessagePack.Tests (net6.0)
   inputs:

sandbox/PerfBenchmarkDotNet/PerfBenchmarkDotNet.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>net472;net5.0</TargetFrameworks>
+    <TargetFrameworks>net472;net6.0</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
   </PropertyGroup>

sandbox/PerfNetFramework/PerfNetFramework.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>net472;net5.0</TargetFrameworks>
+    <TargetFrameworks>net472;net6.0</TargetFrameworks>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
   </PropertyGroup>
   <ItemGroup>

src/MessagePack.Generator/MessagePack.Generator.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <AssemblyName>mpc</AssemblyName>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net6.0</TargetFrameworks>
     <LangVersion>10</LangVersion>
     <Nullable>enable</Nullable>
     <IsPackable>true</IsPackable>

src/MessagePack/MessagePack.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netcoreapp3.1;net6.0</TargetFrameworks>
     <NoWarn>$(NoWarn);CS0649</NoWarn>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
     <DefineConstants Condition=" '$(TargetFramework)' != 'netstandard2.0' ">$(DefineConstants);SPAN_BUILTIN</DefineConstants>

tests/MessagePack.Tests/MessagePack.Tests.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net472;netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net472;netcoreapp3.1;net6.0</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <LangVersion>10</LangVersion>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>