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

hack/update-generated-code.sh

@@ -19,15 +19,14 @@ set -o nounset
 set -o pipefail
 
 SCRIPT_ROOT=$(unset CDPATH && cd $(dirname "${BASH_SOURCE[0]}")/.. && pwd)
-#cd $ROOT
-#SCRIPT_ROOT=$(dirname ${BASH_SOURCE})/..
+
 CODEGEN_PKG=${CODEGEN_PKG:-$(cd ${SCRIPT_ROOT}; ls -d -1 ./vendor/k8s.io/code-generator 2>/dev/null || echo ../code-generator)}
 
 # generate the code with:
 # --output-base    because this script should also be able to run inside the vendor dir of
 #                  k8s.io/kubernetes. The output-base is needed for the generators to output into the vendor dir
 #                  instead of the $GOPATH directly. For normal projects this can be dropped.
-${CODEGEN_PKG}/generate-groups.sh "deepcopy,client,informer,lister" \
+bash ${CODEGEN_PKG}/generate-groups.sh "deepcopy,client,informer,lister" \
   github.com/kubernetes-csi/external-snapshotter/pkg/client github.com/kubernetes-csi/external-snapshotter/pkg/apis \
   volumesnapshot:v1beta1 \
   --go-header-file ${SCRIPT_ROOT}/hack/boilerplate.go.txt