Relax @nestjs/graphql optional dependency

[holm]

This relaxes the optional dependency, so @nestjs/graphql v9 can be used

[andreialecu]

Note that optionalDependencies is incorrect here, that is only for optional native modules.

This should be defined using peerDependencies and peerDependenciesMeta to mark it optional.

See: https://stackoverflow.com/questions/62047806/optional-peer-dependency/66228639

[ntegral]

@holm thanks for the update!