WIP: Update Mill build tooling

[lefou]

• Update mill bootstrap script to 0.13.0-M2-3-ba7090
• Update Mill from 0.11.13 to 0.12.10
• Update Java setup - Mill 0.12 required Java 11 at build time, but the project should still support running on Java 8 at runtime.
• mill-integrationtest plugin doesn't work out-of-the-box with Mill 0.12
• Renew build script, fix deprecations

[ghostbuster91]

Hey,
just saw this PR - looks like it would fix an issue we're currently facing at work. I noticed there hasn’t been much activity recently, and totally understand if it’s just a matter of not having the time (we've all been there 😄).

If you're open to it, we'd be happy to help push this over the finish line. Let us know if that would be helpful - or if you already have something in the works.

Thanks for getting this started in the first place!

[lefou]

@ghostbuster91 I haven't worked on this, so please feel free to move forward. Your help is greatly appreciated!

Just to be clear, this PR is about building this plugin with a newer Mill version. It's not about building this plugin for a newer Mill version (e.g. 1.0), which can be perfectly done without bumping Mill for now.

It would be interesting though, which issue the update might fix for you? If you have an issue with this plugin, opening a new issue might be the best way to start getting it fixed, beside contributing the fix.

[ghostbuster91]

@lefou Got it, thanks! The issue on our end is that we’re using Mill 0.12, which the current version of the plugin doesn’t support.

As far as I can tell, there’s currently no PR that adds 0.12 support, so if you don’t mind, we’ll pick this effort up and create one.

[lefou]

@lefou Got it, thanks! The issue on our end is that we’re using Mill 0.12, which the current version of the plugin doesn’t support.

As far as I can tell, there’s currently no PR that adds 0.12 support, so if you don’t mind, we’ll pick this effort up and create one.

Please open an issue for it and include the error message. To my knowledge, this plugin does work with Mill 0.12. We don't have integration tests for it, but I think I saw it opening pull requests against projects using Mill 0.12. Mill 0.12 uses the same binary platform as Mill 0.11 and plugins should be compatible.

Related:

• https://github.com/scala-steward-org/mill-plugin/pull/57/files