README: update IRC network and links

We are no longer on Freenode for a while now.

README.md

@@ -135,11 +135,11 @@ Before creating an issue or ticket, please double check for duplicates!
 
 Want to quickly get in touch with us for a question, or even just to talk?
 
-You will always find someone from the VLC team on IRC, __#videolan__ channel on the freenode network.
+You will always find someone from the VLC team on IRC, __#videolan__ channel on the Libera Chat network.
 
 For VLC-iOS specific questions, you can find us on __#vlc-ios__.
 
-If you don't have an IRC client, you can always use the [freenode webchat](https://webchat.freenode.net/).
+If you don't have an IRC client, you can always use the [Libera Chat webchat](https://web.libera.chat/?channels=#videolan,%23vlc-ios).
 
 ## Code of Conduct