Update the introspection/validation middleware to use automatic authentication by default

Author: kevinchalet

src/AspNet.Security.OAuth.Introspection/OAuthIntrospectionOptions.cs

@@ -15,6 +15,8 @@ namespace AspNet.Security.OAuth.Introspection {
     public class OAuthIntrospectionOptions : AuthenticationOptions {
         public OAuthIntrospectionOptions() {
             AuthenticationScheme = OAuthIntrospectionDefaults.AuthenticationScheme;
+            AutomaticAuthenticate = true;
+            AutomaticChallenge = true;
         }
 
         /// <summary>

src/AspNet.Security.OAuth.Validation/OAuthValidationOptions.cs

@@ -13,6 +13,8 @@ namespace AspNet.Security.OAuth.Validation {
     public class OAuthValidationOptions : AuthenticationOptions {
         public OAuthValidationOptions() {
             AuthenticationScheme = OAuthValidationDefaults.AuthenticationScheme;
+            AutomaticAuthenticate = true;
+            AutomaticChallenge = true;
         }
 
         /// <summary>

src/Owin.Security.OAuth.Introspection/OAuthIntrospectionOptions.cs

@@ -16,6 +16,7 @@ namespace Owin.Security.OAuth.Introspection {
     public class OAuthIntrospectionOptions : AuthenticationOptions {
         public OAuthIntrospectionOptions()
             : base(OAuthIntrospectionDefaults.AuthenticationScheme) {
+            AuthenticationMode = AuthenticationMode.Active;
         }
 
         /// <summary>

src/Owin.Security.OAuth.Validation/OAuthValidationOptions.cs

@@ -14,6 +14,7 @@ namespace Owin.Security.OAuth.Validation {
     public class OAuthValidationOptions : AuthenticationOptions {
         public OAuthValidationOptions()
             : base(OAuthValidationDefaults.AuthenticationScheme) {
+            AuthenticationMode = AuthenticationMode.Active;
         }
 
         /// <summary>