[add] NET 6 support

[add] .NET Standard 2.1 support
[up] Microsoft.Extensions.Configuration bump to 3.1.32

Author: i4004

src/Simplify.Mail/CHANGELOG.md

@@ -1,5 +1,16 @@
 # Changelog
 
+## [1.5.5] - 2022-09-08
+
+### Added
+
+- .NET 6 support
+- .NET Standard 2.1 support
+
+### Dependencies
+
+- Microsoft.Extensions.Configuration bump to 3.1.32
+
 ## [1.5.4] - 2022-09-08
 
 ### Fixed

src/Simplify.Mail/Simplify.Mail.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 	<PropertyGroup>
-		<TargetFrameworks>netstandard2.0;net462</TargetFrameworks>
+		<TargetFrameworks>net6.0;netstandard2.1;netstandard2.0;net48</TargetFrameworks>
 		<LangVersion>latest</LangVersion>
 		<EmbedUntrackedSources>true</EmbedUntrackedSources>
 		<IncludeSymbols>true</IncludeSymbols>
@@ -21,12 +21,12 @@
 		<PackageReleaseNotes>See https://github.com/SimplifyNet/Simplify/tree/master/src/Simplify.Mail/CHANGELOG.md for details</PackageReleaseNotes>
 	</PropertyGroup>
 	<ItemGroup>
-		<PackageReference Include="Microsoft.Extensions.Configuration" Version="3.1.*" />
+		<PackageReference Include="Microsoft.Extensions.Configuration" Version="3.1.32" />
 	</ItemGroup>
-	<ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
+	<ItemGroup Condition=" '$(TargetFramework)' == 'net6.0' Or '$(TargetFramework)' == 'netstandard2.1' Or '$(TargetFramework)' == 'netstandard2.0' ">
 		<PackageReference Include="System.Configuration.ConfigurationManager" Version="4.7.0" />
 	</ItemGroup>
-	<ItemGroup Condition=" '$(TargetFramework)' == 'net462' ">
+	<ItemGroup Condition=" '$(TargetFramework)' == 'net48' ">
 		<Reference Include="System" />
 		<Reference Include="System.Configuration" />
 	</ItemGroup>