removed flask-restplus and replaced with flask-restx

backend/api/recorder_api.py

@@ -9,7 +9,7 @@ from datetime import datetime
 from pprint import pprint
 
 from flask_jwt_extended import jwt_required
-from flask_restplus import fields, Resource, inputs
+from flask_restx import fields, Resource, inputs
 
 from backend import db, app
 from backend.api import api_recorder