[TASK] fix typo + update UPGRADE.md

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 `sgYoutubeLightbox.js` (vanilla JS).
+`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```