Transfer maintenance and resurrect graphql-subscriptions

We at The Guild finally got again a production use case to use this library and we saw that the library was unmaintained for a couple of years.

So we would love to resurrect the library and bring it up to speed.

Will the kind people at Apollo be open to transfer the maintenance of that package to The Guild to give it and the community of users and other pubs integration authors a new life?

It might save the community from the hassle of moving to another package like [what happened with the `subscriptions-transport-ws` library](https://the-guild.dev/blog/graphql-over-websockets)

(a lot of the original code was written by @dotansimha and myself so I'm sure it will stay in good hands)

Thank you

@grantwwu @hwillson

No files, tests, or entry points are named. Start by reviewing the repository context and the request for maintenance transfer, then seek a decision from Apollo and The Guild maintainers; the issue is done only when ownership and an ongoing maintenance plan are agreed.

Written by the indexing model from the issue text.