Packer
plugins install
The plugins install subcommand installs a Packer plugin at a version constraint
$ packer plugins install -h
Usage: packer plugins install <plugin> [<version constraint>]
  This command will install the most recent compatible Packer plugin matching
  version constraint. When the version constraint is omitted, the most recent
  version will be installed.
  Ex: packer plugins install github.com/hashicorp/happycloud v1.2.3
Related
packer initwill install all required plugins.