Update Community-Events.md (graphql#208)

Added GraphQL London meetup.

Author: gsans

site/community/Community-Events.md

@@ -111,6 +111,7 @@ Use this opportunity to ask him questions about this topic and a good excuse to
 
 - [GraphQL Amsterdam](https://www.meetup.com/Amsterdam-GraphQL-Meetup/)
 - [GraphQL Berlin](https://www.meetup.com/graphql-berlin/)
+- [GraphQL London](https://www.meetup.com/GraphQL-London)
 - [GraphQL Paris](https://www.meetup.com/GraphQL-Paris/)
 
 ### Australia