Offering to maintain GraphAPI

Problem/Motivation

I want to leave https://www.drupal.org/project/graphapi as a maintainer and the first step is to make co-maintainer

- https://www.drupal.org/u/joachim

the owner of the project

- https://www.drupal.org/node/902868/maintainers

so he can drop me as a maintainer eventually.

Thanks!