gallery-dl: Update to 1.12.2

Changes:
1.12.2
------
### Additions
- [deviantart] match new search/popular URLs (#538)
- [deviantart] match `/favourites/all` URLs (#555)
- [deviantart] add extractor for followed users (#515)
- [pixiv] support listing followed users (#515)
- [imagefap] handle beta.imagefap.com URLs (#552)
- [postprocessor:metadata] add `directory` option (#520)

### Fixes
- [artstation] fix search result pagination (#537)
- [directlink] send Referer headers (#536)
- [exhentai] restrict default directory name length (#545)
- [mangadex] change domain to mangadex.cc (#559)
- [mangahere] send `isAdult` cookies (#556)
- [newgrounds] fix tags metadata extraction
- [pixiv] retry after rate limit errors (#535)
- [twitter] handle quoted tweets (#526)
- [twitter] handle API rate limits (#526)
- [twitter] fix URLs forwarded to youtube-dl (#540)
- prevent infinite recursion when spawning new extractors (#489)
- improve output of `--list-keywords` for "parent" extractors (#548)
- provide fallback for SQLite versions with missing `WITHOUT ROWID`
  support (#553)

(leot)