Bump mockito-core from 2.25.1 to 2.28.2
Bump mockito-core from 2.25.1 to 2.28.2

Bumps [mockito-core](https://github.com/mockito/mockito) from 2.25.1 to 2.28.2.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v2.25.1...v2.28.2)
gocd-contrib/docker-swarm-elastic-agents,gocd-contrib/docker-swarm-elastic-agents,gocd-contrib/docker-swarm-elastic-agents