Fix ProxyAttribute<T> (#85)

* Fix ProxyAttribute<T>

* public Type Type { get; }

Author: StefH

src/ProxyInterfaceSourceGenerator/FileGenerators/ExtraFilesGenerator.cs

@@ -57,6 +57,7 @@ public ProxyAttribute(Type type, bool proxyBaseClasses, ProxyClassAccessibility
     [AttributeUsage(AttributeTargets.Interface)]
     internal sealed class ProxyAttribute<T> : Attribute where T : class
     {{
+        public Type Type {{ get; }}
         public bool ProxyBaseClasses {{ get; }}
         public ProxyClassAccessibility Accessibility {{ get; }}
         public {stringArray} MembersToIgnore {{ get; }}