labhub.py: Change invite alias

Change invite alias from 'invite' to 'welcome'.

Closes #166

Author: Alexander Voronkov

plugins/labhub.py

@@ -96,7 +96,7 @@ def TEAMS(self, new):
         self._teams = new
 
     # Ignore LineLengthBear, PycodestyleBear
-    @re_botcmd(pattern=r'^(?:(?:invite)|(?:inv))\s+(?:(?:@?([\w-]+)(?:\s*(?:to)\s+(\w+))?)|(me))$',
+    @re_botcmd(pattern=r'^(?:(?:welcome)|(?:inv)|(?:invite))\s+(?:(?:@?([\w-]+)(?:\s*(?:to)\s+(\w+))?)|(me))$',
                re_cmd_name_help='invite [to team]')
     def invite_cmd(self, msg, match):
         """