1. update clientset, deepcopy using code-generator

2. add a dummy file tools.go to force "go mod vendor" to see
code-generator as dependencies
3. add a script to update CRD
4. add a README to document CRD updating steps
run go mod tidy
update README

vendor/k8s.io/code-generator/go.mod

@@ -0,0 +1,30 @@
+// This is a generated file. Do not edit directly.
+
+module k8s.io/code-generator
+
+go 1.12
+
+require (
+	github.com/emicklei/go-restful v2.9.5+incompatible // indirect
+	github.com/go-openapi/jsonreference v0.19.3 // indirect
+	github.com/go-openapi/spec v0.19.3 // indirect
+	github.com/gogo/protobuf v1.2.2-0.20190723190241-65acae22fc9d
+	github.com/json-iterator/go v1.1.8 // indirect
+	github.com/mailru/easyjson v0.7.0 // indirect
+	github.com/modern-go/reflect2 v1.0.1 // indirect
+	github.com/spf13/pflag v1.0.5
+	github.com/stretchr/testify v1.4.0 // indirect
+	golang.org/x/net v0.0.0-20191004110552-13f9640d40b9 // indirect
+	golang.org/x/tools v0.0.0-20190920225731-5eefd052ad72 // indirect
+	gonum.org/v1/gonum v0.0.0-20190331200053-3d26580ed485
+	gonum.org/v1/netlib v0.0.0-20190331212654-76723241ea4e // indirect
+	gopkg.in/yaml.v2 v2.2.4 // indirect
+	k8s.io/gengo v0.0.0-20190822140433-26a664648505
+	k8s.io/klog v1.0.0
+	k8s.io/kube-openapi v0.0.0-20191107075043-30be4d16710a
+)
+
+replace (
+	golang.org/x/sys => golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a // pinned to release-branch.go1.13
+	golang.org/x/tools => golang.org/x/tools v0.0.0-20190821162956-65e3620a7ae7 // pinned to release-branch.go1.13
+)