youtube-dl 2020.11.19

Core

• [extractor/common] Output error for invalid URLs in _is_valid_url (#21400,
  #24151, #25617, #25618, #25586, #26068, #27072)

Extractors

• [youporn] Fix upload date extraction
• [youporn] Make comment count optional (#26986)
• [arte] Rework extractors
  • Reimplement embed and playlist extractors to delegate to the single
    entrypoint artetv extractor
  • Improve embeds detection (#27057)

• [arte] Extract m3u8 formats (#27061)

• [mgtv] Fix format extraction (#26415)

• [lbry] Add support for odysee.com (#26806)

• [francetv] Improve info extraction

• [francetv] Add fallback video URL extraction (#27047)