Log Message:
youtube-dl: Update to 20210108

Changes:
version 2021.01.08
------------------
Core
* [downloader/hls] Disable decryption in tests (#27660)
+ [utils] Add a function to clean podcast URLs

Extractors
* [rai] Improve subtitles extraction (#27698, #27705)
* [canvas] Match only supported VRT NU URLs (#27707)
+ [bibeltv] Add support for bibeltv.de (#14361)
+ [bfmtv] Add support for bfmtv.com (#16053, #26615)
+ [sbs] Add support for ondemand play and news embed URLs (#17650, #27629)
* [twitch] Drop legacy kraken API v5 code altogether and refactor
* [twitch:vod] Switch to GraphQL for video metadata
* [canvas] Fix VRT NU extraction (#26957, #27053)
* [twitch] Switch access token to GraphQL and refactor (#27646)
+ [rai] Detect ContentItem in iframe (#12652, #27673)
* [ketnet] Fix extraction (#27662)
+ [dplay] Add suport Discovery+ domains (#27680)
* [motherless] Improve extraction (#26495, #27450)
* [motherless] Fix recent videos upload date extraction (#27661)
* [nrk] Fix extraction for videos without a legalAge rating
- [googleplus] Remove extractor (#4955, #7400)
+ [applepodcasts] Add support for podcasts.apple.com (#25918)
+ [googlepodcasts] Add support for podcasts.google.com
+ [iheart] Add support for iheart.com (#27037)
* [acast] Clean podcast URLs
* [stitcher] Clean podcast URLs
+ [xfileshare] Add support for aparat.cam (#27651)
+ [twitter] Add support for summary card (#25121)
* [twitter] Try to use a Generic fallback for unknown twitter cards (#25982)
+ [stitcher] Add support for shows and show metadata extraction (#20510)
* [stv] Improve episode id extraction (#23083)

version 2021.01.03
------------------
Extractors
* [nrk] Improve series metadata extraction (#27473)
+ [nrk] Extract subtitles
* [nrk] Fix age limit extraction
* [nrk] Improve video id extraction
+ [nrk] Add support for podcasts (#27634, #27635)
* [nrk] Generalize and delegate all item extractors to nrk
+ [nrk] Add support for mp3 formats
* [nrktv] Switch to playback endpoint
* [vvvvid] Fix season metadata extraction (#18130)
* [stitcher] Fix extraction (#20811, #27606)
* [acast] Fix extraction (#21444, #27612, #27613)
+ [arcpublishing] Add support for arcpublishing.com (#2298, #9340, #17200)
+ [sky] Add support for Sports News articles and Brighcove videos (#13054)
+ [vvvvid] Extract akamai formats
* [vvvvid] Skip unplayable episodes (#27599)
* [yandexvideo] Fix extraction for Python 3.4