feat: support add generic type custom function (#365)

* feat: support add generic type custom function

* fix: not support .NET 4.5.2

* fix: indeterminate sorting of GetImplicitRolesForUser

Author: Taoyuesong

Casbin.Benchmark/TestHelper.cs

@@ -6,7 +6,7 @@ public static class TestHelper
     {
         public static string GetTestFilePath(string fileName)
         {
-            return Path.Combine("examples", fileName);
+            return Path.Combine("Examples", fileName);
         }
     }
 }

Casbin.UnitTests/Casbin.UnitTests.csproj

@@ -4,7 +4,7 @@
     <TargetFrameworks>net9.0;net8.0;net7.0;net6.0;net5.0;netcoreapp3.1;net462;net461;net452</TargetFrameworks>
     <DebugType>full</DebugType>
     <IsPackable>false</IsPackable>
-    <LangVersion>10.0</LangVersion>
+    <LangVersion>latest</LangVersion>
     <EnforceCodeStyleInBuild>false</EnforceCodeStyleInBuild>
   </PropertyGroup>