Drop .NET 5 and add .NET 7

Resolves #111

Author: Jericho

Source/HttpMultipartParser.Benchmark/HttpMultipartParser.Benchmark.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

Source/HttpMultipartParser.UnitTests/HttpMultipartParser.UnitTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net48;netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net48;net6.0;net7.0</TargetFrameworks>
     <AssemblyName>HttpMultipartParser.UnitTests</AssemblyName>
     <RootNamespace>HttpMultipartParser.UnitTests</RootNamespace>
   </PropertyGroup>

Source/HttpMultipartParser/HttpMultipartParser.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net48;netstandard2.1;net5.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net48;netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <LangVersion>preview</LangVersion>
     <PlatformTarget>anycpu</PlatformTarget>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>