chore: update and add required packages

__init__.py

-# from flask_marshmallow import Marshmallow
 from flask_restx import Api
-
 from flask import Flask
 
-# import os
 
 __all__ = [
     "formats",

requirements-dev.txt

+Flask
+flask-restx
+flasgger
+flask-marshmallow
+openapi-schema-validator==0.4.1
+openapi-spec-validator==0.5.2
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requirements.txt

 Flask
 flask-restx
 flasgger
-flask-marshmallow
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