removed flask-restplus and replaced with flask-restx

backend/api/example_api.py

@@ -5,7 +5,7 @@ import json
 import logging
 from random import *
 from flask import jsonify, Blueprint, request
-from flask_restplus import Resource, reqparse
+from flask_restx import Resource, reqparse
 
 from backend import basic_auth, multi_auth, db, jwt_auth
 from backend.api import api_v1, api_bp