Update dpy version

[rtk-rnjn]

Update dpy version in requirements.txt as lot many old features started getting deprecated.

[Tom-the-Bomb]

This library has been unmaintained for a while now, as I have quit discord development (hence also have not been keeping up with new discord API / discord.py updates). I wouldn't be surprised if anything broke. It's just here for people to use and modify / fork (also why it's not published).
You are more than welcome to make a fork and update things.

However I dont think updating d.py requirements from 1.7.3 min to 2.x would break anything, but at the same time its just a minimum requirement, and if you already have d.py installed prior it wont downgrade it or anything, but I'll check and update it