Add `--clean` flag to just copy the file without making any changes

[fregante]

ghat will prepend this text to every workflow:

env: {}

# DO NOT EDIT BELOW, USE: npx ghat fregante/ghatemplates/is-dist-up-to-date

If you just want to use ghat without it mentioning itself, there should be a flag to avoid any changes to the YAML file.