increase max retries from 3 to 20
increase max retries from 3 to 20

mkuzmin/packer,youhong316/packer,mitchellh/packer,timsutton/packer,rnaveiras/packer,ricardclau/packer,pecigonzalo/packer,grubernaut/packer,youhong316/packer,dave2/packer,hashicorp/packer,dave2/packer,pecigonzalo/packer,youhong316/packer,hashicorp/packer,rnaveiras/packer,pecigonzalo/packer,bryson/packer,paulmey/packer,mitchellh/packer,mkuzmin/packer,timsutton/packer,rnaveiras/packer,tb3088/packer,tas50/packer,timsutton/packer,tas50/packer,ricardclau/packer,grubernaut/packer,tb3088/packer,ricardclau/packer,paulmey/packer,timsutton/packer,ricardclau/packer,paulmey/packer,tas50/packer,bryson/packer,dave2/packer,tb3088/packer,mkuzmin/packer,rnaveiras/packer,tas50/packer,mkuzmin/packer,hashicorp/packer,mkuzmin/packer,youhong316/packer,mkuzmin/packer,tb3088/packer,bryson/packer,paulmey/packer,tb3088/packer,paulmey/packer,tas50/packer,grubernaut/packer,pecigonzalo/packer,ricardclau/packer,bryson/packer,mitchellh/packer,grubernaut/packer,tb3088/packer,paulmey/packer,rnaveiras/packer,rnaveiras/packer,dave2/packer,mitchellh/packer,dave2/packer,youhong316/packer,mitchellh/packer,bryson/packer,grubernaut/packer,dave2/packer,grubernaut/packer,tas50/packer,youhong316/packer,bryson/packer,timsutton/packer,timsutton/packer,ricardclau/packer,hashicorp/packer