Update config.json - remove class topic from space age (#854)
Update config.json - remove class topic from space age (#854)

Student mentioned that this exercise had a class tag, which caused confusion. This exercise is no longer a class based exercise, therefore I've removed this tag.
tejasbubane/xecmascript,exercism/xecmascript,exercism/xecmascript,tejasbubane/xecmascript