v3.17.0 - Spleeter 5-stem model (with piano)

Added

• Support Spleeter's 5-stem model which separates piano in addition to other accompaniment

Changed

• Update separator form UI to use buttons instead of dropdown menus
• Improve form field validation
• Bring back 'iterations' param for X-UMX model
• Fix Dev Docker Compose config
• Fix bug where deleting dynamic mix may cause blank screen
• Update dependencies

Removed

• Remove frontend upload size check and rely on Nginx and backend instead