Revert back to using the encoding/json pkg for NewEncoder and NewDecoder. These weren't exactly compatible

pkg/util/json/json.go

@@ -8,8 +8,9 @@ import (
 
 var Marshal = gojson.Marshal
 var Unmarshal = gojson.Unmarshal
-var NewEncoder = gojson.NewEncoder
-var NewDecoder = gojson.NewDecoder
+
+var NewEncoder = json.NewEncoder
+var NewDecoder = json.NewDecoder
 
 type Marshaler = json.Marshaler
 type Unmarshaler = json.Unmarshaler