[FEATURE] use project_theme_lightbox instead of magnific-popup

- added new sgVimeoLightbox.js which uses LightboxManager
- added deprecation notice to vimeoLightbox.js
- updated README
- updated UPGRADE

README.md

@@ -58,3 +58,7 @@ times in a row, or that the plugin is on an uncached page. The TYPO3 registry is
 on the fly.
 
 If the `?disableVimeoCache=1` parameter is added to the URL, this cache will be ignored as well.
+
+### .htaccess
+
+Requires `img-src https://i.vimeocdn.com;`, `script-src https://player.vimeo.com;` and `connect-src https://cdn.plyr.io;`.

Resources/Public/JavaScript/sgVimeoLightbox.js

+'use strict';
+
+import LightboxManager from 'lightboxManager';
+
+export default class SgVimeoLightbox {
+
+	/**
+	 * Initializes the LightboxManager with the necessary parameters.
+	 */
+	constructor() {
+		LightboxManager.init({type: 'video', glightbox: {selector: '.sg-vimeo-item'}});
+	}
+}
+

Resources/Public/JavaScript/vimeoLightbox.js

 /**
  * JavaScript module for the sg-vimeo plugin
  *
+ * @deprecated since version 1.1.0 and will be removed in 2.0.0
  */
 module.exports = function() {
 	'use strict';

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).
+Extension project_theme_lightbox required starting with version 2.0.0.