v1.21.2

Additions

• [deviantart] implement pagination option (#2488)
• [pixiv] implement background option (#623, #1124, #2495)
• [postprocessor:ugoira] report ffmpeg/mkvmerge errors (#2487)

Fixes

• [cyberdrop] match cyberdrop.to URLs (#2496)
• [e621] fix 403 errors (#2533)
• [issuu] fix extraction (#2483)
• [mangadex] download from available chapters despite externalUrl (#2503)
• [photovogue] update domain and api endpoint (#2494)
• [sexcom] add fallback for empty files (#2485)
• [twitter] improve syndication video selection (#2354)
• [twitter] fix various syndication issues (#2499, #2354)
• [vk] fix extraction (#2512)
• [weibo] fix infinite retries for deleted accounts (#2521)
• [postprocessor:ugoira] use compatible paths with mkvmerge (#2487)
• [postprocessor:ugoira] do not auto-select the image2 demuxer (#2492)