Update OWNERS approvers and reviewers: hack/jenkins

hack/jenkins/OWNERS

-assignees:
-  - fejta
-  - ixdy
-  - rmmh
-  - spxtr
+approvers:
+- fejta
+- ixdy
+- rmmh
+- spxtr
+reviewers:
+- thockin
+- lavalamp
+- wojtek-t
+- yujuhong
+- brendandburns
+- caesarxuchao
+- vishh
+- mikedanese
+- nikhiljindal
+- bprashanth
+- ixdy
+- gmarek
+- erictune
+- pmorie
+- sttts
+- quinton-hoole
+- dchen1107
+- saad-ali
+- zmerlynn
+- luxas
+- janetkuo
+- justinsb
+- pwittrock
+- roberthbailey
+- yifan-gu
+- eparis
+- mwielgus
+- jlowdermilk
+- soltysh
+- piosz
+- jbeda
+- dims
+- spxtr
+- madhusudancs
+- fejta
+- jayunit100
+- jszczepkowski
+- euank
+- fgrzadkowski
+- satnam6502