chore: update owners

This updates the owners (and aliases) to reduce unecessary notifcations
and review requests.

Signed-off-by: Richard Case <[email protected]>

Author: richardcase

OWNERS

@@ -2,15 +2,13 @@
 
 approvers:
   - sig-cluster-lifecycle-leads
-  - cluster-api-admins
   - cluster-api-aws-admins
   - cluster-api-aws-maintainers
 
 reviewers:
   - cluster-api-aws-admins
   - cluster-api-aws-maintainers
   - cluster-api-aws-reviewers
-  - cluster-api-maintainers
 
 emeritus_approvers:
   - AverageMarcus

OWNERS_ALIASES

@@ -6,17 +6,6 @@ aliases:
     - justinsb
     - neolit123
     - vincepri
-  cluster-api-admins:
-    - fabriziopandini
-    - sbueringer
-    - vincepri
-  cluster-api-maintainers:
-    - chrischdi
-    - enxebre
-    - fabriziopandini
-    - killianmuldoon
-    - sbueringer
-    - vincepri
   cluster-api-aws-admins:
     - richardcase
   cluster-api-aws-maintainers: