ci: make labels in tests lowercase temporarily
ci: make labels in tests lowercase temporarily

This is to account for the bug in capitalization in docker swarm
affinity.

stevenlin598/quilt,tejasmanohar/quilt,kelda/kelda,akshayknarayan/quilt,ZhongtianWang/quilt,kklin/kelda,kklin/quilt,LuiseV/quilt,secant/quilt,quilt/quilt,akshayknarayan/quilt,kklin/quilt,LuiseV/quilt,akshayknarayan/quilt,PenguinToast/quilt,mmussomele/quilt,kelda/kelda,kklin/kelda,secant/quilt,kklin/kelda,mmussomele/quilt,kayousterhout/quilt,PenguinToast/quilt,NetSys/quilt,stevenlin598/quilt,mmussomele/quilt,stevenlin598/quilt,kelda/kelda,kayousterhout/quilt,LuiseV/quilt,quilt/quilt,mmussomele/quilt,NetSys/quilt,ejj/quilt-dev,LuiseV/quilt,PenguinToast/quilt,ZhongtianWang/quilt,tejasmanohar/quilt,kayousterhout/quilt,ZhongtianWang/quilt,tejasmanohar/quilt,secant/quilt,stevenlin598/quilt,kklin/quilt,NetSys/quilt,LuiseV/quilt,mmussomele/quilt,kayousterhout/quilt,kklin/quilt,PenguinToast/quilt,kelda/kelda,akshayknarayan/quilt,ejj/quilt-dev,ejj/quilt-dev,mmussomele/quilt,ejj/quilt-dev,stevenlin598/quilt,PenguinToast/quilt,ZhongtianWang/quilt,stevenlin598/quilt,kklin/kelda,NetSys/quilt,NetSys/quilt,tejasmanohar/quilt,secant/quilt,secant/quilt,quilt/quilt,quilt/quilt