Bump version to 6.0.0-develop (#27598)

apps/meteor/.docker/Dockerfile.rhel

 FROM registry.access.redhat.com/ubi8/nodejs-12
 
-ENV RC_VERSION 5.5.0-develop
+ENV RC_VERSION 6.0.0-develop
 
 MAINTAINER buildmaster@rocket.chat
 

apps/meteor/app/utils/rocketchat.info

 {
-	"version": "5.5.0-develop"
+	"version": "6.0.0-develop"
 }

apps/meteor/package.json

 {
 	"name": "@rocket.chat/meteor",
 	"description": "The Ultimate Open Source WebChat Platform",
-	"version": "5.5.0-develop",
+	"version": "6.0.0-develop",
 	"private": true,
 	"author": {
 		"name": "Rocket.Chat",

package.json

 {
 	"name": "rocket.chat",
-	"version": "5.5.0-develop",
+	"version": "6.0.0-develop",
 	"description": "Rocket.Chat Monorepo",
 	"main": "index.js",
 	"private": true,