chore: Fix length of cluster for gardener integration test (#774)

Makefile

@@ -372,7 +372,7 @@ $(KYMA):
 GIT_COMMIT_SHA=$(shell git rev-parse --short=8 HEAD)
 GIT_COMMIT_DATE=$(shell git show -s --format=%cd --date=format:'v%Y%m%d' ${GIT_COMMIT_SHA})
 HIBERNATION_HOUR=$(shell echo $$(( ( $(shell date +%H | sed s/^0//g) + 5 ) % 24 )))
-GARDENER_CLUSTER_NAME=$(shell echo "test-${GIT_COMMIT_SHA}-${GARDENER_K8S_VERSION}" | sed 's/\.//g')
+GARDENER_CLUSTER_NAME=$(shell echo "ci-${GIT_COMMIT_SHA}-${GARDENER_K8S_VERSION}" | sed 's/\.//g')
 
 ifneq (,$(GARDENER_SA_PATH))
 GARDENER_K8S_VERSION_FULL=$(shell kubectl --kubeconfig=${GARDENER_SA_PATH} get cloudprofiles.core.gardener.cloud gcp -o go-template='{{range .spec.kubernetes.versions}}{{if and (eq .classification "supported") (lt .version "${GARDENER_K8S_VERSION}.a") (gt .version "${GARDENER_K8S_VERSION}")}}{{.version}}{{end}}{{end}}')