feat: Add 'openBrowser' config option

[pascalduez]

• Add a new no-open command line option

Sadly I couldn't go with a more straightforward option like --open since command-line-args disallow configurable Boolean options like --open=false. See 75lb/command-line-args#71

The other solution is --open=on|off

Or using --open but changing the current behavior and not forcing it by default.
My preference :)

Note: The config key will override the command line option, if any

[markdalgleish]

Thanks for this PR too! 😄

Similarly to #14, would you be able to implement this as an openBrowser option in the config file, with a default value of true? I'd still like to keep the default behaviour, since it's a much better experience for newcomers to the project who won't know which URL to open.

[markdalgleish]

Published as v0.4.0. Thank you! 😄