Log Message:
youtube-dl: Update to 20210407

Changes:
20210407
--------
Core
* [extractor/common] Use compat_cookies_SimpleCookie for _get_cookies
+ [compat] Introduce compat_cookies_SimpleCookie
* [extractor/common] Improve JSON-LD author extraction
* [extractor/common] Fix _get_cookies on python 2 (#20673, #23256, #20326,
  #28640)

Extractors
* [youtube] Fix extraction of videos with restricted location (#28685)
+ [line] Add support for live.line.me (#17205, #28658)
* [vimeo] Improve extraction (#28591)
* [youku] Update ccode (#17852, #28447, #28460, #28648)
* [youtube] Prefer direct entry metadata over entry metadata from playlist
  (#28619, #28636)
* [screencastomatic] Fix extraction (#11976, #24489)
+ [palcomp3] Add support for palcomp3.com (#13120)
+ [arnes] Add support for video.arnes.si (#28483)
+ [youtube:tab] Add support for hashtags (#28308)