Update youtube-dl to version 2020.06.06
Release notes can be viewed here
Mainly restores twitch-stream functionality as well as subtitles for brightcove.
Signed-off-by: Tobias Manske <email@example.com>
Test Plan: I'm currently watching Drake live using youtube-dl and mpv, which is currently broken in the previous release.
Reviewers: Triage Team, DataDrake
Reviewed By: Triage Team, DataDrake
Differential Revision: https://dev.getsol.us/D9003