add wa community fork

docs/workadventure.en.md

@@ -23,6 +23,7 @@ As the software changes very fast we can't provide an always up to date howto, b
 
 There are several community forks, trying to ease deployment or integrating stale MRs:
 
+* [https://github.com/workadventure-xce/workadventure-xce](https://github.com/workadventure-xce/workadventure-xce)
 * [https://github.com/tabascoeye/workadventure](https://github.com/tabascoeye/workadventure)
 * [https://gitlab.hasi.it/herzi/project/workadventure](https://gitlab.hasi.it/herzi/project/workadventure)
 * [https://git.binary-kitchen.de/noby/workadventure](https://git.binary-kitchen.de/noby/workadventure)