lock to `windows` cookbook 1.8.6
lock to `windows` cookbook 1.8.6

This works around a regression introduced by [COOK-2729].
mwrock/omnibus,opscode-cookbooks/omnibus,fujin/omnibus,lusis/omnibus,robbydyer/omnibus,rhass/omnibus-cookbook,zsiddique/omnibus,OpsRockin/omnibus,elafarge/omnibus,chef-cookbooks/omnibus