Fix links to go builder
Fix links to go builder

These were relative links, which were broken by the repo move.
GoogleCloudPlatform/cloud-builders-community,GoogleCloudPlatform/cloud-builders-community,GoogleCloudPlatform/cloud-builders-community,GoogleCloudPlatform/cloud-builders-community,GoogleCloudPlatform/cloud-builders-community,GoogleCloudPlatform/cloud-builders-community,GoogleCloudPlatform/cloud-builders-community,GoogleCloudPlatform/cloud-builders-community