fix: update GINKGO_FOCUS in Makefile to include 'GKE workload cluster creation'

Author: afarbos

Makefile

@@ -168,7 +168,7 @@ test: $(SETUP_ENVTEST) ## Run unit and integration tests
 	KUBEBUILDER_ASSETS="$(KUBEBUILDER_ASSETS)" go test ./... $(TEST_ARGS)
 
 # Allow overriding the e2e configurations
-GINKGO_FOCUS ?= Workload cluster creation
+GINKGO_FOCUS ?=  (GKE workload|Workload) cluster creation
 GINKGO_SKIP ?= API Version Upgrade
 GINKGO_NODES ?= 1
 GINKGO_NOCOLOR ?= false