Support for detecting beta version of Chrome or Firefox on Mac

[pz325]

On Mac, we've installed beta version of Chrome or Firefox alongside with the main release.

However, james-browser-launcher detects only the main releases:

[ { name: 'firefox',
    version: '59.0.2',
    type: 'firefox',
    command: '/Applications/Firefox.app' },
  { name: 'chrome',
    version: '66.0.3359.139',
    type: 'chrome',
    command: '/Applications/Google Chrome.app' },
  { name: 'safari',
    version: '11.1',
    type: 'safari',
    command: '/Applications/Safari.app' } ]

Run mdfind kMDItemCFBundleIdentifier=="com.google.Chrome" gives:

/Applications/Google Chrome.app
/Applications/Google Chrome Beta.app

and Run mdfind kMDItemCFBundleIdentifier=="org.mozilla.firefox" gives:

/Applications/Firefox.app
/Applications/Firefox Beta.app

Checked lib/darwin/util.js, not sure how to improve to support detecting both beta and main release? Any advice?