Update rocket.chat

Changes:

https://github.com/RocketChat/Docker.Official.Image/commit/6c060cccf12add88981d25bba5a0ab3b9459bba8

library/rocket.chat

@@ -1,5 +1,5 @@
 Maintainers: Rocket.Chat Image Team <[email protected]> (@RocketChat)
 GitRepo: https://github.com/RocketChat/Docker.Official.Image.git
 
-Tags: 2.0.0, 2.0, 2, latest
-GitCommit: dff5cadb2b10bad4b060b879bcfc5db531ebc82a
+Tags: 2.2.0, 2.2, 2, latest
+GitCommit: 6c060cccf12add88981d25bba5a0ab3b9459bba8