refactor main: Move to Kingpin CLI library

Replace urfave/cli with the kingpin[1] library.

It has slightly more sensible argument validation than the other Go libraries.

Additionally I've opted for removing the '-f / --file' flag in favour of positional arguments to commands.

A previous command like `kontemplate template -f somefile.yml` is now just `kontemplate template somefile.yml`. All other arguments remain the same.

[1]: https://github.com/alecthomas/kingpin

0 files changed, 0 insertions, 0 deletions