update help text for hcl2_upgrade (#10624)
update help text for hcl2_upgrade (#10624)


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