Add @kenafoster to Contributors team

[tylergraff]

I nominate @kenafoster to the Contributors team
Ken currently has 5 contributions merged to the Nebari repo:
https://github.com/nebari-dev/nebari/pulls?q=is%3Apr+author%3Akenafoster+is%3Amerged+

[dcmcand]

@kenafoster has been involved and has a history of contributions to the project. I approve of adding him to the team. If anyone from @nebari-dev/core-team has comments, please add them. Otherwise we will add him.

[dcmcand]

@dharhas can you add @kenafoster to the contributers team?

[dharhas]

invitation sent.