youtube-dl: Update to 20200101

Changes:
20200101
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Extractors
* [brightcove] Invalidate policy key cache on failing requests
* [pornhub] Improve locked videos detection (#22449, #22780)
+ [pornhub] Add support for m3u8 formats
* [pornhub] Fix extraction (#22749, #23082)
* [brightcove] Update policy key on failing requests
* [spankbang] Improve removed video detection (#23423)
* [spankbang] Fix extraction (#23307, #23423, #23444)
* [soundcloud] Automatically update client id on failing requests
* [prosiebensat1] Improve geo restriction handling (#23571)
* [brightcove] Cache brightcove player policy keys
* [teachable] Fail with error message if no video URL found
* [teachable] Improve locked lessons detection (#23528)
+ [scrippsnetworks] Add support for Scripps Networks sites (#19857, #22981)
* [mitele] Fix extraction (#21354, #23456)
* [soundcloud] Update client id (#23516)
* [mailru] Relax URL regular expressions (#23509)

(leot)