stembuild-release should be trigger for clone-base and stem build jobs

[jak74]

The pipeline currently has stembuild-release as a trigger to the update-base job, but the clone-base and stembuild jobs instead trigger off pipeline-resources. If the pipeline-resources git repo hasn't been updated (which it hasn't in months) then the clone-base and stembuild jobs aren't triggering automatically once a new stemcell is released. The pipeline stalls out after the update-base job and the clone-base and stembuild jobs require manual triggers.

I believe that stembuild-release should be a trigger for update-base, clone-base, and stembuild jobs, and pipeline-resources shouldn't be a trigger on any job.