Extended subscriptions-transport-ws to make it work with aws appsync graphql subscription

AWS still used graphql-ws web socket protocol, the package 'graphql-ws' mentioned below does not provide 'graphql-ws' protocol instead it uses 'graphql-transport-ws'

orignal source https://github.com/apollostack/subscriptions-transport-ws.git

follow following link to understand how request will be sent and how url and authentication tokens will be added in payload
https://docs.aws.amazon.com/appsync/latest/devguide/real-time-websocket-client.html

subscriptions-transport-ws is no longer maintained

subscriptions-transport-ws was the first implementation of a WebSocket-based GraphQL subscriptions transport in TypeScript. It was created in 2016 and was largely unmaintained after 2018.

Users should migrate to graphql-ws, a newer actively-maintained implementation of a similar protocol.

Note that the packages implement distinct protocols, so you must migrate all clients and servers.

If you're using subscriptions with the Apollo platform, the Apollo Server docs show how to use graphql-ws with Apollo Server, Apollo Studio Explorer, Apollo Client Web, Apollo iOS, and Apollo Kotlin. If you have more questions about using graphql-ws with the Apollo platform, file an issue on the corresponding repository or post in the community.

The graphql-ws README shows how to integrate graphql-ws with other software.

If you have not yet migrated off of subscriptions-transport-ws and need to learn more about it, you can read the previous version of this file.