DEPS: change clipboard backend to pyclip
Currently, we are using a vendered version of [pyperclip](https://github.com/asweigart/pyperclip). This project was dead for a couple of years. And there were some updates in 2020. But, it's not under active development right now. 

Recently I found this project [pyclip](https://github.com/spyoungtech/pyclip). It looks well maintained and has identical functionalities as pyperclip does. We should investigate if we could replace the vendered pyperclip with pyclip.