Migrate to Newtonsoft.Json 8.0.3

Author: kevinchalet

src/AspNet.Security.OAuth.Introspection/project.json

@@ -30,7 +30,7 @@
     "JetBrains.Annotations": { "type": "build", "version": "10.1.2-eap" },
     "Microsoft.AspNetCore.Authentication": "1.0.0-*",
     "Microsoft.Extensions.Caching.Abstractions": "1.0.0-*",
-    "Newtonsoft.Json": "8.0.2"
+    "Newtonsoft.Json": "8.0.3"
   },
 
   "frameworks": {

src/Owin.Security.OAuth.Introspection/project.json

@@ -31,7 +31,7 @@
     "JetBrains.Annotations": { "type": "build", "version": "10.1.2-eap" },
     "Microsoft.Extensions.Caching.Memory": "1.0.0-*",
     "Microsoft.Owin.Security": "3.0.1",
-    "Newtonsoft.Json": "8.0.2"
+    "Newtonsoft.Json": "8.0.3"
   },
 
   "frameworks": {