[Foundation Board] Board member changes

Directors, We received official notice from Nebula that they are resigning their Gold membership. We also received official notice from Aptira that they are changing Board member representatives. Thank you and best wishes to Chris Kemp, Tristan Goode for their time and efforts, continued support and contributions to the OpenStack Board efforts. Welcome to Roland Chan (Aptira) as a Gold Member Director Regards, AlanClark