add composer tests to root cloudbuild
add composer tests to root cloudbuild

CloudVLab/professional-services,CloudVLab/professional-services,GoogleCloudPlatform/professional-services,CloudVLab/professional-services,GoogleCloudPlatform/professional-services,GoogleCloudPlatform/professional-services,CloudVLab/professional-services,GoogleCloudPlatform/professional-services,GoogleCloudPlatform/professional-services,CloudVLab/professional-services,GoogleCloudPlatform/professional-services,GoogleCloudPlatform/professional-services,CloudVLab/professional-services,CloudVLab/professional-services,GoogleCloudPlatform/professional-services,GoogleCloudPlatform/professional-services