updated libre chat to selenium slack (#2516)

Author: rpallavisharma

website_and_docs/content/documentation/about/_index.en.md

@@ -23,8 +23,8 @@ and search to see whether or not the issue has been filed already.
 If not, feel free to open one!
 
 Many members of the community 
-are present at the #selenium 
-Libera chat at [Libera.chat](https://libera.chat/).
+are present at the #selenium-docs 
+channel of [Selenium Slack Group](https://inviter.co/seleniumhq).
 Feel free to drop in and ask questions
 and if you get help which you think could be of use within these documents,
 be sure to add your contribution!