Bump retrofitVersion from 2.7.2 to 2.8.0
Bump retrofitVersion from 2.7.2 to 2.8.0

Bumps `retrofitVersion` from 2.7.2 to 2.8.0.

Updates `retrofit` from 2.7.2 to 2.8.0
- [Release notes](https://github.com/square/retrofit/releases)
- [Changelog](https://github.com/square/retrofit/blob/master/CHANGELOG.md)
- [Commits](https://github.com/square/retrofit/compare/parent-2.7.2...parent-2.8.0)

Updates `converter-gson` from 2.7.2 to 2.8.0

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
githinho/orthancAPIClient