use 0.20.6 K8s release (zalando#1495)

Author: FxKu

Makefile

@@ -85,7 +85,7 @@ mocks:
 	GO111MODULE=on go generate ./...
 
 tools:
-	GO111MODULE=on go get k8s.io/[email protected].2
+	GO111MODULE=on go get k8s.io/[email protected].6
 	GO111MODULE=on go get github.com/golang/mock/[email protected]
 	GO111MODULE=on go mod tidy
 

go.mod

@@ -12,11 +12,10 @@ require (
 	github.com/stretchr/testify v1.6.1
 	golang.org/x/crypto v0.0.0-20201203163018-be400aefbc4c
 	golang.org/x/mod v0.4.0 // indirect
-	golang.org/x/tools v0.0.0-20201207204333-a835c872fcea // indirect
 	gopkg.in/yaml.v2 v2.4.0
-	k8s.io/api v0.20.2
-	k8s.io/apiextensions-apiserver v0.19.4
-	k8s.io/apimachinery v0.20.2
-	k8s.io/client-go v0.20.2
-	k8s.io/code-generator v0.19.4
+	k8s.io/api v0.20.6
+	k8s.io/apiextensions-apiserver v0.20.6
+	k8s.io/apimachinery v0.20.6
+	k8s.io/client-go v0.20.6
+	k8s.io/code-generator v0.20.6
 )