plugins.youtube: Improve URL regex.
plugins.youtube: Improve URL regex.

melmorabity/streamlink,beardypig/streamlink,ethanhlc/streamlink,ethanhlc/streamlink,wlerin/streamlink,chhe/streamlink,gravyboat/streamlink,wolftankk/livestreamer,gravyboat/streamlink,chrippa/livestreamer,gtmanfred/livestreamer,Saturn/livestreamer,melmorabity/streamlink,javiercantero/streamlink,chhe/streamlink,programming086/livestreamer,beardypig/streamlink,caorong/livestreamer,okaywit/livestreamer,sbstp/streamlink,bastimeyer/streamlink,sbstp/streamlink,chrippa/livestreamer,bastimeyer/streamlink,flijloku/livestreamer,chhe/livestreamer,Feverqwe/livestreamer,blxd/livestreamer,lyhiving/livestreamer,intact/livestreamer,Dobatymo/livestreamer,mmetak/streamlink,charmander/livestreamer,Dobatymo/livestreamer,Masaz-/livestreamer,caorong/livestreamer,Klaudit/livestreamer,fishscene/streamlink,lyhiving/livestreamer,derrod/livestreamer,back-to/streamlink,Klaudit/livestreamer,back-to/streamlink,chhe/livestreamer,jtsymon/livestreamer,programming086/livestreamer,hmit/livestreamer,gtmanfred/livestreamer,javiercantero/streamlink,okaywit/livestreamer,Saturn/livestreamer,wlerin/streamlink,Feverqwe/livestreamer,wolftankk/livestreamer,mmetak/streamlink,fishscene/streamlink,blxd/livestreamer,hmit/livestreamer,Masaz-/livestreamer,flijloku/livestreamer,charmander/livestreamer,derrod/livestreamer,streamlink/streamlink,intact/livestreamer,jtsymon/livestreamer,streamlink/streamlink