* Breaking Change: Split `mta` command into `stdout` and `mda` commands
* Breaking Change: Require Python `>=3.7`
* Enhancement: Add `help` command
* Enhancement: Add `smtp` command
* Enhancement: Add `--force-address` to email generating commands
* Enhancement: Add `--mda-command` to `mda` command
* Enhancement: Add `--separator` to `stdout` command
* Enhancement: Add `--version` argument
* Enhancement: Add `version` command