added vendors

vendor/k8s.io/api/OWNERS

@@ -0,0 +1,50 @@
+approvers:
+- erictune
+- lavalamp
+- smarterclayton
+- thockin
+- liggitt
+# - bgrant0607 # manual escalations only
+reviewers:
+- brendandburns
+- caesarxuchao
+- davidopp
+- dchen1107
+- deads2k
+- derekwaynecarr
+- dims
+- eparis
+- erictune
+- errordeveloper
+- feiskyer
+- gmarek
+- janetkuo
+- jbeda
+- jsafrane
+- jszczepkowski
+- justinsb
+- krousey
+- lavalamp
+- liggitt
+- luxas
+- madhusudancs
+- mikedanese
+- mwielgus
+- ncdc
+- nikhiljindal
+- piosz
+- pmorie
+- pwittrock
+- roberthbailey
+- rootfs
+- saad-ali
+- smarterclayton
+- soltysh
+- sttts
+- tallclair
+- thockin
+- vishh
+- wojtek-t
+- yifan-gu
+- yujuhong
+- zmerlynn