Remove optimize-css-assets-webpack-plugin

It was not providing much improvement and it was breaking source maps.

package-lock.json

@@ -3189,16 +3189,6 @@
         "is-buffer": "1.1.6"
       }
     },
-    "last-call-webpack-plugin": {
-      "version": "2.1.2",
-      "resolved": "https://registry.npmjs.org/last-call-webpack-plugin/-/last-call-webpack-plugin-2.1.2.tgz",
-      "integrity": "sha512-CZc+m2xZm51J8qSwdODeiiNeqh8CYkKEq6Rw8IkE4i/4yqf2cJhjQPsA6BtAV970ePRNhwEOXhy2U5xc5Jwh9Q==",
-      "dev": true,
-      "requires": {
-        "lodash": "4.17.5",
-        "webpack-sources": "1.1.0"
-      }
-    },
     "lazy-cache": {
       "version": "0.2.7",
       "resolved": "https://registry.npmjs.org/lazy-cache/-/lazy-cache-0.2.7.tgz",
@@ -3795,16 +3785,6 @@
         "wrappy": "1.0.2"
       }
     },
-    "optimize-css-assets-webpack-plugin": {
-      "version": "3.2.0",
-      "resolved": "https://registry.npmjs.org/optimize-css-assets-webpack-plugin/-/optimize-css-assets-webpack-plugin-3.2.0.tgz",
-      "integrity": "sha512-Fjn7wyyadPAriuH2DHamDQw5B8GohEWbroBkKoPeP+vSF2PIAPI7WDihi8WieMRb/At4q7Ea7zTKaMDuSoIAAg==",
-      "dev": true,
-      "requires": {
-        "cssnano": "3.10.0",
-        "last-call-webpack-plugin": "2.1.2"
-      }
-    },
     "os-browserify": {
       "version": "0.3.0",
       "resolved": "https://registry.npmjs.org/os-browserify/-/os-browserify-0.3.0.tgz",

package.json

@@ -37,7 +37,6 @@
     "css-loader": "^0.28.9",
     "extract-text-webpack-plugin": "^3.0.2",
     "node-sass": "^4.7.2",
-    "optimize-css-assets-webpack-plugin": "^3.2.0",
     "postcss-initial": "^2.0.0",
     "postcss-loader": "^2.1.0",
     "postcss-prepend-selector": "^0.3.1",

webpack.config.js

@@ -1,7 +1,6 @@
 const path = require('path');
 const webpack = require('webpack');
 const ExtractTextPlugin = require('extract-text-webpack-plugin');
-const OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin');
 
 module.exports = {
   entry: {
@@ -62,6 +61,5 @@ module.exports = {
       filename: '[name].min.css',
       allChunks: true,
     }),
-    new OptimizeCssAssetsPlugin(),
   ],
 };