chore: clean up owners file

This cleans up the root OWNERS file to follow best-practice and to match
the state of the kubeflow sdk file:
https://github.com/kubeflow/sdk/blob/main/kubeflow/hub/OWNERS

after the following PR is merged:
kubeflow/sdk#252

Specifically this does the following:

- move andreyvelich to emeritus_approvers (no longer active)
  (per this comment: kubeflow/sdk#244 (comment) )
- remove duplicate reviewers entries which are also in approvers:
  - Al-Pragliola
  - pboyd

Also see: kubeflow/sdk#244 (comment)

Following this, these OWNERS files should be kept in sync:
https://github.com/kubeflow/model-registry/blob/main/OWNERS
https://github.com/kubeflow/sdk/blob/main/kubeflow/hub/OWNERS

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

Author: jonburdo

OWNERS

@@ -1,17 +1,14 @@
 approvers:
   - Al-Pragliola
-  - andreyvelich  # noqa(kubeflow-hub-team)
   - ederign
   - jonburdo
   - pboyd
   - rareddy
   - tarilabs
 emeritus_approvers:
+  - andreyvelich
   - ckadner
   - Tomcli
   - zijianjoy
 reviewers:
-  - Al-Pragliola
-  - andreyvelich
   - fege
-  - pboyd