* Update autoscaling annotation validation
see ref: https://github.com/knative/serving/pull/9496
* Replace DeprecatedInjectionAnnotation with InjectionAnnotation
* Vendor deps at master
* Use context.TODO instead of context.Background
* Pin pkg to release-0.18 version
* ./hack/update-deps.sh --upgrade && ./hack/update-codegen.sh
* bump k8s version to 1.18.8
* Fix the brokerage of importing latest serving
* exclude script/test-infra md from md check