feat: update version label to 2.15.0-beta in docusaurus config

Author: radist2s

website/docusaurus.config.js

@@ -51,7 +51,7 @@ const config = {
           lastVersion: 'current',
           versions: {
             current: {
-              label: '2.x',
+              label: '2.15.0-beta',
             },
             '2.14.0': {
               label: '2.14.0',