Create sig-ui kubernetes-sigs config

Author: mrbobbytables

config/kubernetes-sigs/sig-ui/OWNERS

@@ -0,0 +1,8 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+reviewers:
+  - sig-ui-leads
+approvers:
+  - sig-ui-leads
+labels:
+  - sig/ui