Bump projects to .NET 6 and add `DllImport` resolver for iOS

SDL2-CS.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
-        <TargetFramework>netstandard2.0</TargetFramework>
+        <TargetFramework>net6.0</TargetFramework>
         <OutputType>Library</OutputType>
         <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
         <AssemblyTitle>SDL2#</AssemblyTitle>

src/SDL2.cs

@@ -37,6 +37,12 @@ namespace SDL2
 {
 	public static class SDL
 	{
+		static SDL()
+		{
+			if (OperatingSystem.IsIOS())
+				NativeLibrary.SetDllImportResolver(typeof(SDL).Assembly, (_, assembly, path) => NativeLibrary.Load("@rpath/SDL2.framework/SDL2", assembly, path));
+		}
+
 		#region SDL2# Variables
 
 		private const string nativeLibName = "SDL2";