fix(build): remove "browser" field in package.json

There is nothing special in the browser build that is actually practical
for modern use. The "browser" field, as defined in
https://github.com/defunctzombie/package-browser-field-spec#overview,
indicates that you should use it if you are directly accessing globals,
using browser-specific features, dom manipulation, etc.

React components like react-draggable are built to do minimal raw
DOM manipulation, and to always gate this behind conditionals to ensure
that server-side rendering still works. We don't make any changes
to any of that for the "browser" build, so it's entirely redundant.

Hoping this also fixes the "Super expression must either be null or
a function" error (#472) that some users have experienced with particular
bundler configurations.

The browser build may still be imported at "build/web/react-draggable.min.js".
This is to prevent breakage only. The file is no longer minified to prevent
possible [terser bugs](terser/terser#308).

package.json

@@ -3,7 +3,6 @@
   "version": "4.3.1",
   "description": "React draggable component",
   "main": "build/cjs/cjs.js",
-  "browser": "build/web/react-draggable.min.js",
   "module": "build/module/Draggable.js",
   "scripts": {
     "test": "make test",

webpack.config.js

@@ -1,6 +1,5 @@
 const path = require('path');
 const webpack = require('webpack');
-const TerserPlugin = require('terser-webpack-plugin');
 
 // Grabbed in .babelrc.js to switch on transpiling modules.
 // We want webpack to handle modules if possible.
@@ -65,10 +64,6 @@ module.exports = (env, argv) => ({
     new webpack.optimize.ModuleConcatenationPlugin(),
   ],
   optimization: {
-    minimizer: [new TerserPlugin({
-      include: /\.min\.js$/,
-      sourceMap: true,
-      terserOptions: {}
-    })],
+    minimize: false,
   }
 });