Release notes:
- feat: Use VP9 instead of VP8 for WebM recording
- feat: libx264 is no longer required when just recording GIF / APNG with FFmpeg back end
- feat: Removed avconv / libav backend and ImageMagick post processor
- misc: Added sources for DBus interfaces
- fix: Fixed lossy artifacts increasing GIF size when using gnome-shell recorder
- fix: Fixed countdown sometimes appearing in recording
- fix: Do not freeze window size on Xfce
- i18n: Fixed names of Chinese localization files
- i18n: Updated translations for Basque, Chinese (Simplified), Lithuanian, Norwegian Bokmål, Russian, Serbian, Ukrainian
- packaging: Removed Snapcraft build and Snap packages