jsturtevant: Lower concurrency for windows goss

JobBuild
666
07-26 17:17
json-sort-check 1419751511331704832 1419708511939465216
pull-azure-vhds 1419773030590058496 1419751511302344704 1419708511901716480
pull-ova-all 1419708511868162048
pull-packer-validate 1419751511361064960 1419708511968825344