Replace shipkit

[Bukama]

Copied from the xp-repo as test-reports also use shipkit:

Shipkit is deprecated and the GitHub project is archived. They write:

"One Shipkit Gradle plugin to rule them all" approach has proven hard to maintain for the team. We are converted Shipkit into a narrow set of small libraries (design note). Several customers, inclusing Mockito project have already migrated.

We need to investigate whether there is already a replacement ("We are converted" is an unfortunate mistake because it could be "have converted" or "are converting") and then possibly migrate to it. This may also fix #246.

On a side note: Our version of Shipkit uses a deprecated GitHub API that stops working in May. It was fixed, though, so this could be solved by updating Shipkit.