context in SchemaLink is not async

[elsasslegend]

Intended outcome:
I'm trying to have an async context for SchemaLink.
But in "src/link/schema/index.ts" at line 51 there is this.context(operation) instead of await this.context(operation).
This is a different behavior for ApolloClient than for ApolloServer, which breaks the app in my case.

Actual outcome:
context does not wait until promise is resolved, and therefore the injected context in resolvers is wrong.

How to reproduce the issue:
Make the context return a promise instead of a sync function

Versions
Latest version

[benjamn]

@djflex68 Seems like a good idea! Have a look at #6735?