Project lead shouldn't be able to retire its own committer status in a project and just keep PL status
In relation to issue: #148
A Project Lead has the ability to retire committers from their project, however, it shouldn't be possible to retire themselves from the committer role in a project where they are Project Lead.
If a Project Lead wants to retire themselves from the committer role he would need to step down as a project lead as well.
I'm thinking the solution could be displaying a message when a PL tries to retire as committer saying he would need to retire as PL before being able to do so as a committer.