Upgrade to clap for argument parsing

[nick42d]

As mentioned on #28, command line arguments could use an overhaul, so kicking it off with an upgrade to clap since gumdrop seems to be no longer maintained.

I set this up to break as little as possible existing behaviour, if we are willing to change the version flag to clap default -V from -v it removes the need to have a version arg also.

Output of cargo-aur --help - Old

Usage: /home/nickd/.cargo/bin/cargo-aur [OPTIONS]

Positional arguments:
  free                 Absorbs any extra junk arguments.

Optional arguments:
  -h, --help           Display this help message.
  -v, --version        Display the current version of this software.
  -o, --output OUTPUT  Set a custom output directory (default: target/).
  -m, --musl           Use the MUSL build target to produce a static binary.
  -d, --dryrun         Don't actually build anything.

Output of cargo-aur --help - New

Prepare Rust projects to be released on the Arch Linux User Repository.

Usage: cargo-aur [OPTIONS]

Options:
  -o, --output <OUTPUT>  Set a custom output directory (default: target/)
  -m, --musl             Use the MUSL build target to produce a static binary
  -d, --dryrun           Don't actually build anything
  -v, --version          Print version
  -h, --help             Print help

[fosskers]

Thanks for this. I know that gumdrop doesn't see much activity, but clap is a massive dependency and the needs of cargo aur are fairly simple. As-is, this increases the binary size by about 65%, so I'm leaning towards not including this. What do you think?

[nick42d]

Your call here, binary size is not a personal concern for me but understood for some it is.

[fosskers]

clap is otherwise an excellent tool and I use it elsewhere, but in this case I think it doesn't buy us much. Although I'm going to close this, thanks for the effort.