Update PlayFabEditorExtensions.asmdef (#114)

At this moment, the .asmdef will force the EditorExtensions into their own dll (not wrapped into Unity's Editor dll) Which has the consequence that a CompilationPipeline will return the editor extensions when Play is passed in (rather than Editor which it should show up in).

Author: toddbellMSFT

Source/Assets/PlayFabEditorExtensions/PlayFabEditorExtensions.asmdef

@@ -1,3 +1,14 @@
 {
-	"name": "PlayFabEditorExtensions"
-}
+    "name": "PlayFabEditorExtensions",
+    "references": [],
+    "includePlatforms": [
+        "Editor"
+    ],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": false,
+    "precompiledReferences": [],
+    "autoReferenced": true,
+    "defineConstraints": [],
+    "versionDefines": []
+}