build: upgrade to .NET 6

src/Directory.Build.props

@@ -1,6 +1,6 @@
 <Project>
   <PropertyGroup>
-    <TargetFramework>net5.0</TargetFramework>
+    <TargetFramework>net6.0</TargetFramework>
     <Nullable>enable</Nullable>
     <WarningLevel>9999</WarningLevel>
     <!-- <TreatWarningsAsErrors>true</TreatWarningsAsErrors> -->

src/TrashLib/Radarr/CustomFormat/Processors/GuideSteps/ConfigStep.cs

@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using Common.Extensions;
-using MoreLinq.Extensions;
 using TrashLib.Radarr.Config;
 using TrashLib.Radarr.CustomFormat.Models;
 

src/global.json

@@ -0,0 +1,7 @@
+{
+  "sdk": {
+    "version": "6.0",
+    "rollForward": "latestMajor",
+    "allowPrerelease": false
+  }
+}