SpringBoot Raise baseline for native image generation and consider buildpacks

I think the new reachability JSON files means that we'll need to raise the baseline for native image generation. We'll also want to look at how we can make the experience nice with buildpacks.

Comment From: snicoll

@philwebb what do you mean by "how we can make the experience nice with buildpacks."?

Comment From: philwebb

I can't remember exactly what I meant. I might have been ensuring that mvn -Pnative spring-boot:build-image didn't accidentally use an older JDK that has no idea about the new JSON format.