Add PPA install instructions to README

[Wiener234]

Pull Request Template

Type of change

• [ ] Bug fix
• [x] Feature
• [x] Documentation update

Description

*I build a debian package and it is hosted in this PPA "https://github.com/Wiener234/ani-cli-ppa".

I added the install instructions with the GPG Key to the README under the Debian section with.*

Checklist

• [ ] any anime playing
• [ ] bumped version
• [x] next, prev and replay work
• [x] quality works
• [x] downloads work
• [x] quality works with downloads
• [x] select episode -a and rapid resume work
• [x] syncplay -s works
• [x] autoplay, aka range selection, works

Additional Testcases

• The safe bet: One Piece
• Episode 0: Saenai Heroine no Sodatekata ♭
• Unicode: Saenai Heroine no Sodatekata ♭
• Not uploaded: one piece dub episode 590
• Unreleased: soredemo ayumu wa yosetekuru
• Short id (for decryption): Log Horizon episode 1-2

[Derisis13]

I'll close #789 in favour of this. I'll also write a full guide for rpm, and I'd like to see similar ones for the AUR, termux, scoop and brew (at least)

[Derisis13]

This is what I could find. Instructions for brew are missing from v2.2's readme and I can't get my head around the scoop instructions + I'm not even sure if it'd work...

[port19x]

Can we port this PR to include recent readme changes? I do find ppa & copr instructions valuable

[Derisis13]

I'll try to work on this. I'd also like scoop added too, since it's once again maintained