Publish snapshots from workflows

[jvalkeal]

To get 3.0.x snapshots into our artifactory, create a workflow. We probably want to do that
as a successful result of a main CI workflow where build is ran via jfrog cli.

[jvalkeal]

We now have i.e. https://repo.spring.io/ui/native/libs-snapshot/org/springframework/shell/spring-shell-core/3.0.0-SNAPSHOT