Add Matt Crees to OpenStack team

Matt Crees being a core reviewer in several upstream OpenStack projects,
it makes sense to add him to the OpenStack team on GitHub.

Author: priteau

terraform/github/terraform.tfvars.json

@@ -227,6 +227,7 @@
           "cityofships",
           "dougszumski",
           "jovial",
+          "motehue",
           "stackhpc-ci"
         ]
       }