I. Introduction
Smartphones have become an essential part of people's lives due to several applications, like e-shopping, internet banking, internet surfing, social networking, etc. According to Statista, the number of smartphone users worldwide is about 3.8 billion which is expected to increase by several hundred million in the coming few years [1]. Android operating system holds 73% market share as compared to other platforms, and has maintained popularity in the global market as of June 2021 [2]. According to the report of the first quarter of 2021, Google Play Store is the largest app store in the world and has 2.96 million apps available [3].