Stop create_charpente() when license is not provided

[hypebright]

Would be nice if there's a first check to see if the license argument is provided in create_charpente(), otherwise you end up with a half-complete package.

Simple fix:

  if(missing(license)) {
    ui_stop('Please provide a license, e.g. "mit" or "gpl3"')
  }

also update example in roxygen documentation 📝

[DivadNojnarg]

Yes a check could be nice.

Do you think this could default to "mit"? Also this line is quite bad code:

  eval(parse(text = paste0("use_", license, "_license()")))

Instead:

create_charpente <- function(license) {
 eval(substitute(license))
}

so people can pass instead of a string: create_charpente(usethis::use_mit_license())