Fix subscriptions-transport-ws deprecation issue

[seansund]

npm warn deprecated subscriptions-transport-ws@0.11.0: The subscriptions-transport-ws package is no longer maintained. We recommend you use graphql-ws instead. For help migrating Apollo software to graphql-ws, see https://www.apollographql.com/docs/apollo-server/data/subscriptions/#switching-from-subscriptions-transport-ws For general help using graphql-ws, see https://github.com/enisdenjo/graphql-ws/blob/master/README.md