Support --version option

[k-toumura]

• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)

Proposed changes

(Fixes #23) Support --version option.

% node bin/nrlint.js
Error: no input file
Lint tool for Node-RED flows (v1.0.2-git)
    Usage: nrlint [-h] [-c configfile] flows.json

    Options:
      -h, --help                   Show this help
      -c, --config configfile      Configuration file to use, otherwise use .nrlintrc.js
      -f, --format outputFormat    Output format: 'default,json'
      --debug                      Output debugging information
      --init                       Generate a default configuration
      --version                    Output version information and exit

% node bin/nrlint.js --version
1.0.2-git

Checklist

• [x] I have read the contribution guidelines
• [ ] For non-bugfix PRs, I have discussed this change on the forum/slack team.

[linux-foundation-easycla[bot]]

The committers are authorized under a signed CLA.

• :white_check_mark: Kunihiko Toumura (60546f17835037f1cdccc787bf68fecad2159038)