Handle 'mix local.rebar' command options without arguments

[henrythebuilder]

This PR would handle the mix local.rebar task called with no arguments (path for rebar3):

It fix the current error:

mix local.rebar --force
** (Mix) Invalid arguments given to mix local.rebar. To find out the proper call syntax run "mix help local.rebar"

and trace command action:

mix local.rebar --force
* installing Rebar locally from "https://repo.hex.pm/installs/1.13.0/rebar3-3.15.2" with options [sha512: "dc559ace623406453c424debbcccb3eca3d40403920f6be0e240f5ec7e8f2836886fd3a3d6355e06d924781143f1275c35067e8ad7d1fe0995e35e74dedc6f17", force: true]
* creating /home/user/.mix/elixir/1.14.0/rebar3

[josevalim]

💚 💙 💜 💛 ❤️

[henrythebuilder]

Thanks!