update CHANGELOG
update CHANGELOG

* Tidy up existing changelog entries

hashicorp/packer,mitchellh/packer,ricardclau/packer,hashicorp/packer,rnaveiras/packer,pecigonzalo/packer,rnaveiras/packer,ricardclau/packer,ricardclau/packer,rnaveiras/packer,mitchellh/packer,rnaveiras/packer,rnaveiras/packer,mitchellh/packer,ricardclau/packer,rnaveiras/packer,pecigonzalo/packer,pecigonzalo/packer,hashicorp/packer,ricardclau/packer,pecigonzalo/packer,hashicorp/packer,mitchellh/packer,mitchellh/packer,ricardclau/packer