Bump mixlib-cli to 2.1.5
Bump mixlib-cli to 2.1.5

This pull request was triggered automatically via Expeditor when mixlib-cli 2.1.5 was promoted to Rubygems.

This change falls under the obvious fix policy so no Developer Certificate of Origin (DCO) sign-off is required.

MsysTechnologiesllc/chef,gene1wood/chef,tas50/chef-1,nvwls/chef,nvwls/chef,mattray/chef,higanworks/chef,higanworks/chef,nvwls/chef,tas50/chef-1,jaymzh/chef,MsysTechnologiesllc/chef,nvwls/chef,chef/chef,tas50/chef-1,gene1wood/chef,tas50/chef-1,mattray/chef,MsysTechnologiesllc/chef,jaymzh/chef,mwrock/chef,mattray/chef,mwrock/chef,chef/chef,higanworks/chef,mwrock/chef,jaymzh/chef,mattray/chef,mwrock/chef,MsysTechnologiesllc/chef,higanworks/chef,higanworks/chef,nvwls/chef,gene1wood/chef,chef/chef,chef/chef,jaymzh/chef,nvwls/chef,mattray/chef,gene1wood/chef