Log Message:
gallery-dl: Update to 1.27.6

Changes:
1.27.6
======
- [ao3] add `subscriptions` extractor
- [boosty] add support
- [civitai] add `post` extractors
- [pixiv] support unlisted artworks
- Several bug fixes and improvements

1.27.5
======
- [ao3] add support
- [civitai] add support
- [cohost] add support
- Several bug fixes and improvements

1.27.4
======
- [sexcom] add `likes` extractor
- [wikimedia] add `wiki` extractor
- Several bug fixes and improvements