chore(hub): add kubeflow hub approver jonburdo (#252)

The main kubeflow hub repo added jonburdo to the OWNERS file in this PR:
kubeflow/hub#2162

This makes the same change to kubeflow/hub/OWNERS

Signed-off-by: Jon Burdo <jon@jonburdo.com>

Author: jonburdo

kubeflow/hub/OWNERS

@@ -1,6 +1,7 @@
 approvers:
   - Al-Pragliola
   - ederign
+  - jonburdo
   - pboyd
   - rareddy
   - tarilabs
@@ -11,4 +12,3 @@ emeritus_approvers:
   - zijianjoy
 reviewers:
   - fege
-  - jonburdo