Add cleanup async change to CHANGELOG.
Add cleanup async change to CHANGELOG.

broccolijs/broccoli,ember-cli/broccoli,broccolijs/broccoli,broccolijs/broccoli,gabesoft/broccoli,ixisystems/broccoli,gabesoft/broccoli,osxi/broccoli,ixisystems/broccoli,osxi/broccoli,ember-cli/broccoli,broccolijs/broccoli,ember-cli/broccoli,gabesoft/broccoli,osxi/broccoli