Move the test resource out of `./webhook`. (#32)

This is so that other things can more naturally write tests using this same test resource.

hack/update-codegen.sh

@@ -25,7 +25,7 @@ go install ./vendor/k8s.io/code-generator/cmd/deepcopy-gen
 
 # Depends on generate-groups.sh to install bin/deepcopy-gen
 ${GOPATH}/bin/deepcopy-gen --input-dirs \
-  github.com/knative/pkg/logging,github.com/knative/pkg/webhook/testing \
+  github.com/knative/pkg/logging,github.com/knative/pkg/testing \
   -O zz_generated.deepcopy \
   --go-header-file ${PKG_ROOT}/hack/boilerplate/boilerplate.go.txt
 

webhook/webhook_test.go

@@ -42,7 +42,7 @@ import (
 	fakekubeclientset "k8s.io/client-go/kubernetes/fake"
 
 	. "github.com/knative/pkg/logging/testing"
-	. "github.com/knative/pkg/webhook/testing"
+	. "github.com/knative/pkg/testing"
 )
 
 func newDefaultOptions() ControllerOptions {