Support for Webpack 4?

[Nickersoft]

Are there any plans to adapt this plugin for Webpack 4? I could try my hand at a pull request if you're too busy. Currently using this plugin with Webpack 4 renders the following error:

ERROR in   TypeError: callback is not a function
      
      - index.js:65 HtmlWebpackPugPlugin.preProcessHtml
        [homepage]/[html-webpack-pug-plugin]/index.js:65:3
      
      - index.js:14 
        [homepage]/[html-webpack-pug-plugin]/index.js:14:12
      
      
      - new Promise
      
      
      - Hook.js:35 AsyncSeriesWaterfallHook.lazyCompileHook [as _promise]
        [homepage]/[tapable]/lib/Hook.js:35:21
      
      - index.js:645 
        [homepage]/[html-webpack-plugin]/index.js:645:47
      
      - index.js:173 Promise.resolve.then.then.then.then.then.then.html
        [homepage]/[html-webpack-plugin]/index.js:173:18
      
      
      - next_tick.js:160 process._tickCallback
        internal/process/next_tick.js:160:7

[Nickersoft]

@negibouze Went ahead and made a PR: #16

[negibouze]

@Nickersoft Thank you for your Report & PR.

[negibouze]

@Nickersoft
I released a new version(v0.3.0).
Thank you for your cooperation :)