Update youtube-dl to 2020.9.6

[pyup-bot]

This PR updates youtube-dl from 2020.7.28 to 2020.9.6.

Changelog

2020.09.06

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))

Links

• PyPI: https://pypi.org/project/youtube-dl
• Changelog: https://pyup.io/changelogs/youtube-dl/
• Repo: https://github.com/ytdl-org/youtube-dl

[pyup-bot]

Closing this in favor of #2299