Expiry Time for Developer Memberships

== Reason ==
Members of teams often go inactive. These members simply sit in the team taking up space when they don't intend to actually do anything. Sometimes a reminder is needed to keep this user active or for them to declare their intent to remain involved with the project.

== Proposal ==
Set an account expiry time of 180 days (6 months) on the vomun-developers team which will prompt members to apply for membership renewal. This should be granted unless there is a reason for this user to be removed from the team (such as vandalism, bad reviews, security vulnerabilities, low edit quality, etc).