Admin when team members step down

The following is a list of actions that need to be taken when a team member steps down from the project

• Remove Google Groups access (@acrymble)
• Remove Google Analytics access (@acrymble)
• Remove Github Jekyll access (@mdlincoln)
• Remove from ProgHist Ltd register of members (@drjwbaker)
• Remove Twitter access (@jenniferisasi)
• Change team: true to team: false, and add team_end: YYYY to the _data/ph_authors.yml file to remove the person from the Project Team page (@acrymble)
• Check that they have no open issues assigned to them on either the Jekyll repository or the Submissions Repository (@acrymble).
• If they hold any other team roles, inform @acrymble that a replacement is needed.

Wish them well, and invite them to keep in touch.