ci: use KOCACHE for image build (#5723)

Makefile

@@ -24,6 +24,7 @@ HELM_OPTS ?= --set serviceAccount.annotations.eks\\.amazonaws\\.com/role-arn=${K
 KARPENTER_NAMESPACE ?= kube-system
 KARPENTER_VERSION ?= $(shell git tag --sort=committerdate | tail -1 | cut -d"v" -f2)
 KO_DOCKER_REPO ?= ${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_DEFAULT_REGION}.amazonaws.com/dev
+KOCACHE ?= ~/.ko
 
 # Common Directories
 MOD_DIRS = $(shell find . -path "./website" -prune -o -name go.mod -type f -print | xargs dirname)
@@ -121,7 +122,7 @@ licenses: download ## Verifies dependency licenses
 	! go-licenses csv ./... | grep -v -e 'MIT' -e 'Apache-2.0' -e 'BSD-3-Clause' -e 'BSD-2-Clause' -e 'ISC' -e 'MPL-2.0'
 
 image: ## Build the Karpenter controller images using ko build
-	$(eval CONTROLLER_IMG=$(shell $(WITH_GOFLAGS) KO_DOCKER_REPO="$(KO_DOCKER_REPO)" ko build --bare github.com/aws/karpenter-provider-aws/cmd/controller))
+	$(eval CONTROLLER_IMG=$(shell $(WITH_GOFLAGS) KOCACHE=$(KOCACHE) KO_DOCKER_REPO="$(KO_DOCKER_REPO)" ko build --bare github.com/aws/karpenter-provider-aws/cmd/controller))
 	$(eval IMG_REPOSITORY=$(shell echo $(CONTROLLER_IMG) | cut -d "@" -f 1 | cut -d ":" -f 1))
 	$(eval IMG_TAG=$(shell echo $(CONTROLLER_IMG) | cut -d "@" -f 1 | cut -d ":" -f 2 -s))
 	$(eval IMG_DIGEST=$(shell echo $(CONTROLLER_IMG) | cut -d "@" -f 2))