Upgrade to graphql-java 15

[smyrick]

See the release notes: https://github.com/graphql-java/graphql-java/releases/tag/v15.0

• Includes new directive in the spec @specifiedBy
• Removed extended scalars from the schema
• Included bug fix Fix SchemaPrinter to exclude braces while printing types with no fields. graphql-java/graphql-java#1798

[ruibritopt]

Hello could the community persuade the codeowners to merge this PR? @smyrick put in the work and I for one can make great use of it, so I would really appreciate it if we could have a release soon. Thank you.

[nihalgonsalves]

@sachindshinde could you please take a look at this? It's blocking us from upgrading. Thanks!

[sachindshinde]

@smyrick @nihalgonsalves Sorry for the delays here, I'll review the PR

[nikolayandr]

Guys, would be really nice to have this MR merged, it stops us to upgrade on graphql-java#15

[kosmos]

Please, merge MR.

[nikolayandr]

@sachindshinde could you please tell us about plans when this MR is going to be merged? Thanks

[sachindshinde]

@smyrick @nihalgonsalves @nikolayandr @kosmos
Apologies for the wait here.

Updates to FederationSdlPrinter need to be handled in a particular way when doing graphql-java upgrades. Specifically, the newer version of SchemaPrinter needs to be copied over FederationSdlPrinter, and then the changeset that was applied to the older version of SchemaPrinter to turn it into FederationSdlPrinter needs to be replayed on top of the newer version of SchemaPrinter (with any now-unneeded bugfix backports removed). This is done to ensure any bugfixes and subtle changes reflected in the newer SchemaPrinter are included in FederationSdlPrinter (e.g. the bugfix at graphql-java/graphql-java#1832 ).

I've iterated on this PR, and filed PR #73 . Review shouldn't take long, although we'd like to test an RC in Apollo's infrastructure first before making a release, as this has caught bugs in the past.