Update graphql-java to version 24.2 - fix nullable types support in Kotlin

[bbattezzati]

graphql-java/java-dataloader 4.0.0 and 5.0.0 has broken nullable types support in Kotlin

A ticket was opened to address the issue:
graphql-java/java-dataloader#195

then it was fixed as part of:
graphql-java/java-dataloader#207
and https://github.com/graphql-java/java-dataloader/releases/tag/v5.0.1

So a new release was created, with the fix: https://github.com/graphql-java/graphql-java/releases/tag/v24.2

Can you please update the dependency

[bclozel]

@bbattezzati thanks for raising this. We did see the new version prior to our release yesterday, but decided to skip this one for now. While we agree that nullable type support in Kotlin is important, this release also introduces a mandatory dependency to kotlin-stdlib and this will be a major problem for Java and Kotlin applications.

We will upgrade to the next release as soon as it's out. In the meantime, you can choose to manually upgrade in your application (beware, the kotlin library version might not be the one you are using in your application).

Thanks!

[bclozel]

@bbattezzati See #1321