reenable gkeconnect in quickstart ci builds

[scotthart]

gkeconnect needs a release cycle to switch from using grpc connection headers to rest connection heads in the quickstart builds that rely on previous releases on google-cloud-cpp

[dbolduc]

When the time comes, we should also see if we can get it to run successfully instead of expecting errors

google-cloud-cpp/google/cloud/gkeconnect/CMakeLists.txt

Lines 29 to 40 in 20b1a94

	COMMAND
	cmake -P "${PROJECT_SOURCE_DIR}/cmake/quickstart-runner.cmake"
	$<TARGET_FILE:gkeconnect_quickstart> GOOGLE_CLOUD_PROJECT
	GOOGLE_CLOUD_CPP_TEST_REGION
	# use GOOGLE_CLOUD_CPP_BIGTABLE_TEST_INSTANCE_ID as input
	# membership-id. we don't expect it to be valid.
	GOOGLE_CLOUD_CPP_BIGTABLE_TEST_INSTANCE_ID)
	set_tests_properties(
	gkeconnect_quickstart
	PROPERTIES
	LABELS "integration-test;quickstart" PASS_REGULAR_EXPRESSION
	"google::cloud::Status thrown: INVALID_ARGUMENT: Permanent error")