title: how to run gulp tasks from webpack
body: <p>I have recently updated gulp to 4+ version and then gulp does not start the watch tasks anymore. 
  What am i doing wrong? below here is the updated version of code gulp 3+ to gulp 4, I am using gulp.series as per gulp4 docs.</p>
  
  <p><code>npm run build</code> command would have previously copied over the assets folder to 2 other places, its not anymore starting the gulp tasks and gulp watch.</p>
  
  <p>Given myGulpFile.js </p>
  
  <pre><code>var gulp = require('gulp');
  var path = require('path');
  
  gulp.task('copytask', function() {
      gulp.src(['assets/**/*']).pipe(gulp.dest('buildpath/assets'))
          .pipe(gulp.dest(path.resolve(__dirname, '../somepath/assets')));
  });
  gulp.task('watchtask', gulp.series( function watchtask(){
      gulp.watch('assets/**/*', gulp.series('copytask'));
  }));
  gulp.task('default',gulp.series('watchtask', function (done) {
      console.log("Gulp started now from webpack!!");
  done();
  }));
  
  </code></pre>
  
  <p>Given my package.json for webpack</p>
  
  <pre><code>  "main": "webpack.config.js",
    "scripts": {
      "build": "webpack --progress -c",
      "watch": "webpack -w --progress -c",
      "dev": "webpack-dev-server --devtool eval --progress --colors --content-base build",
      "deploy": "NODE_ENV=production webpack --config webpack.production.config.js"
    },
  </code></pre>
  
  <p>and my webpack.config.js</p>
  
  <pre><code>var webpack = require('webpack');
  var something ...;
  
  require('./myGulpFile');
  
  var config = {
  ...
  }
  
  module.exports = config;
  </code></pre>
  
  <p>any help regarding this is much appreciated!</p>
  
  <p>EDIT: To further clarify my question, I want to run gulp by running just one of the webpack commands and automatically start the gulp tasks (this was happening in gulp3+ version using above procedure) but broke after updating to gulp4 version.</p>