Support argv as second config param

Explain the problem

Sometimes a developer wants to access webpacks internal command line options in his config.

Expected Behaviour

The config function should pass two params into the config function:

• An environment as the first parameter. See the environment options CLI documentation for syntax examples.
• An options map (argv) as the second parameter. This describes the options passed to webpack, with keys such as output-filename and optimize-minimize.

source

Actual Behaviour

parallel-webpack omits the second param (argv).

Provide your webpack config

module.exports = (env, argv) => {
     console.log('isEnvSet', !!env)
     console.log('isArgvSet', !!argv)
     return {}
}

Steps to reproduce

Use the config above and run:

parallel-webpack --config=webpack.config.js

Provide your Environment details

• Node version: v9.1.0
• Operating System: MacOS 10.13.3
• webpack version: 3.11.0
• parallel-webpack version: 2.3.0