replace "dep" with "go mod"

A simple "go mod init && go mod tidy && go mod vendor" was enough and
mostly seems to have picked the same revisions of the dependencies as
before. Notable exceptions are klog and gogo/protobuf.

vendor/k8s.io/client-go/tools/record/OWNERS

@@ -0,0 +1,29 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+reviewers:
+- lavalamp
+- smarterclayton
+- wojtek-t
+- deads2k
+- derekwaynecarr
+- caesarxuchao
+- vishh
+- mikedanese
+- liggitt
+- nikhiljindal
+- erictune
+- pmorie
+- dchen1107
+- saad-ali
+- luxas
+- yifan-gu
+- eparis
+- mwielgus
+- timothysc
+- jsafrane
+- dims
+- krousey
+- a-robinson
+- aveshagarwal
+- resouer
+- cjcullen