Update CHANGELOG.md to reflect the promotion of 0.19.16
Update CHANGELOG.md to reflect the promotion of 0.19.16

Obvious fix; these changes are the result of automation not creative thinking.

chef/knife-ec2,MsysTechnologiesllc/knife-ec2,ClogenyTechnologies/knife-ec2,MsysTechnologiesllc/knife-ec2,chef/knife-ec2