Update OWNERS approvers and reviewers: pkg/master

pkg/master/OWNERS

-assignees:
-  - derekwaynecarr
-  - lavalamp
-  - mikedanese
-  - nikhiljindal
+approvers:
+- derekwaynecarr
+- lavalamp
+- mikedanese
+- nikhiljindal
+reviewers:
+- thockin
+- lavalamp
+- smarterclayton
+- wojtek-t
+- deads2k
+- yujuhong
+- derekwaynecarr
+- caesarxuchao
+- mikedanese
+- liggitt
+- nikhiljindal
+- bprashanth
+- gmarek
+- erictune
+- davidopp
+- pmorie
+- sttts
+- dchen1107
+- saad-ali
+- luxas
+- janetkuo
+- justinsb
+- roberthbailey
+- ncdc
+- timstclair
+- mwielgus
+- timothysc
+- soltysh
+- piosz
+- jbeda
+- dims
+- madhusudancs
+- hongchaodeng
+- krousey
+- jayunit100
+- jszczepkowski