Log Message:
youtube-dl: Update to 20200906

pkgsrc changes:
* Update patch for the [rai] extractor (only related to tests)

Changes:
20200906
--------
Core
+ [utils] Recognize wav mimetype (#26463)

Extractors
* [nrktv:episode] Improve video id extraction (#25594, #26369, #26409)
* [youtube] Fix age gate content detection (#26100, #26152, #26311, #26384)
* [youtube:user] Extend URL regular expression (#26443)
* [xhamster] Improve initials regular expression (#26526, #26353)
* [svtplay] Fix video id extraction (#26425, #26428, #26438)
* [twitch] Rework extractors (#12297, #20414, #20604, #21811, #21812, #22979,
  #24263, #25010, #25553, #25606)
    * Switch to GraphQL
    + Add support for collections
    + Add support for clips and collections playlists
* [biqle] Improve video ext extraction
* [xhamster] Fix extraction (#26157, #26254)
* [xhamster] Extend URL regular expression (#25789, #25804, #25927))