Update Version to 3.1.3 (#533)

Author: JoC0de

src/NuGetForUnity/Editor/NugetPreferences.cs

@@ -11,7 +11,7 @@ public class NugetPreferences : SettingsProvider
         /// <summary>
         ///     The current version of NuGet for Unity.
         /// </summary>
-        public const string NuGetForUnityVersion = "3.1.1";
+        public const string NuGetForUnityVersion = "3.1.3";
 
         /// <summary>
         ///     The current position of the scroll bar in the GUI.

src/NuGetForUnity/package.json

@@ -1,7 +1,7 @@
 {
     "name": "com.github-glitchenzo.nugetforunity",
     "displayName": "NuGetForUnity",
-    "version": "3.1.1",
+    "version": "3.1.3",
     "description": "A NuGet Package Manager for Unity",
     "unity": "2018.4",
     "keywords": [