title: How to upload assets to s3 from webpack
body: <p>I'm new to webpack.I want to upload my minified js file to s3 using webpack.I used follwing code in webpack.config.js file.</p>
  
  <pre><code>   const webpack = require('webpack');
  var S3Plugin = require('webpack-s3-plugin');
  
       module.exports = {
           entry: './src/app.js',
           output: {
               path: './bin',
               filename: 'app.bundle.js'
           },
            plugins: [
              new webpack.optimize.UglifyJsPlugin({
                  compress: {
                      warnings: false,
                  },
                  output: {
                      comments: false,
                  },
              }),
              new S3Plugin({
            // Only upload css and js
            include: /.*\.(css|js)/,
            // s3Options are required
            s3Options: {
              accessKeyId: 'key',
              secretAccessKey: 'key',
              region: 'Oregon',
              signatureVersion: 'v4',
       /*       s3BucketEndpoint: true,*/
              endpoint: "endpoint"
            },
            s3UploadOptions: {
              Bucket: 'bucketname'
            }
          })
          ]
       };
  </code></pre>
  
  <p>but i'm getting following error in webpack <strong>ERROR in S3Plugin: Error: Non-file stream objects are not supported with SigV4 in AWS.S3</strong> how can i solve this issue?</p>