UPGRADE.md

# Version 1.X.X to Version 2.0.0

`vimeoLightbox.js` (deprecated since 1.1.0) using magnific-popup and jQuery removed in favor of `sgVimeoLightbox.js` (vanilla JS).
Extension project_theme_lightbox required starting with version 2.0.0.

## Version 1.1  ```project_theme_lightbox``` integration
- The magnific popup integration is deprecated and will be removed in later versions.
- Implement JavaScript according to the readme after integrating ```project_theme_lightbox```