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/github.com/go-openapi/spec/.golangci.yml

@@ -0,0 +1,23 @@
+linters-settings:
+  govet:
+    check-shadowing: true
+  golint:
+    min-confidence: 0
+  gocyclo:
+    min-complexity: 45
+  maligned:
+    suggest-new: true
+  dupl:
+    threshold: 200
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+
+linters:
+  enable-all: true
+  disable:
+    - maligned
+    - unparam
+    - lll
+    - gochecknoinits
+    - gochecknoglobals