Update OWNERS file to use approvers

Not sure we've ever used a field called "maintainers"

Base approvers on existing github teams that have write or admin
access to this repo, plus SIG leads

OWNERS

@@ -1,16 +1,9 @@
-maintainers:
+# See the OWNERS docs: https://git.k8s.io/community/docs/devel/owners.md
-  - adamreese
+
-  - bacongobbler
+approvers:
-  - jascott1
+  - sig-apps-leads
-  - michelleN
+  - helm-admins
-  - migmartri
+  - helm-maintainers
-  - nebril
-  - prydonius
-  - seh
-  - technosophos
-  - thomastaylor312
-  - vaikas-google
-  - viglesiasce
 reviewers:
   - adamreese
   - bacongobbler

OWNERS_ALIASES

@@ -0,0 +1,21 @@
+# See the OWNERS docs: https://git.k8s.io/community/docs/devel/owners.md
+
+aliases:
+  sig-apps-leads:
+    - michelleN
+    - mattfarina
+    - prydonius
+    - kow3ns
+  helm-admins:
+    - sgoings
+    - technosophos
+    - vaikas-google
+  helm-maintainers:
+    - technosophos
+    - sgoings
+    - sparkprime
+    - michelleN
+    - sebgoa
+    - adamreese
+    - bmelville
+    - vaikas-google