fix(buildFederatedSchema): Export GraphQLSchemaModule type

[jtomaszewski]

We have a big app that uses @apollo/federation and we have several modules defined separately, with their own tests etc. in their folders. Each module exports const module: GraphQLSchemaModule = { typeDefs, resolvers } which are then glued together and passed to buildFederatedSchema.

However currently the GraphQLSchemaModule must be imported from apollo-graphql which is a dependency of @apollo/federation and we see little need in adding that as a direct dependency of our app.

This however triggers such an eslint warning for us:

Which is annoying as we have to ignore it all over the files. ( // eslint-disable-next-line import/no-extraneous-dependencies )

As GraphQLSchemaModule is type definition of an argument of buildFederatedSchema, it belongs to the public API of @apollo/federation, and this is why I think it should be exported by the @apollo/federation itself.

Thus, the PR.

[apollo-cla]

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[trevor-scheer]

Thanks for the PR @jtomaszewski - appreciate the explanation and this seems like a reasonable ask. This LGTM! Would you mind adding an entry to the federation-js/CHANGELOG.md?

[jtomaszewski]

Done. When merging this, I suggest doing "Squash and merge", to merge the commits into one.

[trevor-scheer]

Done! Sorry for the delay on this @jtomaszewski. This change will go out with the next release.