Use gradle-build-action for invoking Gradle on CI

[bigdaz]

The gradle/gradle-build-action replaces eskatos/gradle-command-action, and v2 brings a number of improvements around caching and usability.

[simonbasle]

thanks for the suggestion @bigdaz !
this looks good to me.

would you be willing however to re-target this PR on the 3.3.x branch? (github workflows should be the same there).

also have a single doubt on the last set of arguments (see inline comment)

[bigdaz]

PR rebased on 3.3.x branch and publish.yml fixed as requested.

[simonbasle]

checks are still shown as "waiting" despite at least one restarted and passing. I'll just close and reopen this PR to force a trigger of checks again.

[reactorbot]

@simonbasle this PR seems to have been merged on a maintenance branch, please ensure the change is merge-forwarded to intermediate maintenance branches and up to main 🙇

[simonbasle]

wait, these are not only replacing the eskatos usage, but also the run usage. we decided that for publishing artifacts we'd avoid 3rd party gh actions as much as possible. I'll revert that part on 3.3.x before forward merging the CI.yml change only. (edit: left also the test step to use gradle's action).

[bigdaz]

Thanks for merging, and yes I took the liberty of updating all Gradle invocations. Apologies if that wasn't desired.