Outdated GraphQL Java tutorial

Hi,

I am one of the maintainer of GraphQL Java.

The GraphQL Java tutorial by @kaqqao is unfortunately outdated and also uses some third party libraries on top of GraphQL Java, without making it clear that it is actually not GraphQL Java itself. Our experience has shown that this is confusing for beginners. Our recommend approach can be found here

Please consider adding a warning message which makes it clear that it is outdated and that this is not the recommend getting started approach for GraphQL Java or maybe just remove it all at the moment.

Just to be clear: I think the tutorial was very helpful overall and thanks a lot to @kaqqao for writing the tutorial in the first place while nobody else picked up the task.

The library itself and the ecosystem have evolved and I just wanna make sure that this is reflected somehow.

Thanks a lot, Andi