title: serverless-webpack can't resolve module
body: <p>Getting this error from serverless-webpack:</p>
  
  <pre><code>ERROR in ../db/actions/index.js
  Module not found: Error: Can't resolve 'amazon-dax-client' in '/var/task/db/actions'
   @ ../db/actions/index.js 2:24-52
   @ ../db/db.js
   @ ./crop.js
  </code></pre>
  
  <p>My webpack.config.js file contains:</p>
  
  <pre><code>const slsw = require('serverless-webpack')
  
  module.exports = {
      entry: slsw.lib.entries,
      target: 'node',
      externals: {
          sharp: 'commonjs sharp',
      },
      // Run babel on all .js files and skip those in node_modules
      module: {
          rules: [{
              test: /\.js$/,
              loader: 'babel-loader',
              include: __dirname,
              exclude: /node_modules/,
          }]
      }
  }
  </code></pre>
  
  <p>The <code>amazon-dax-client</code> module is present in node_modules.</p>
  
  <p>I've rolled back to the last versions of webpack and serverless-webpack that worked for me:</p>
  
  <pre><code>"serverless-webpack": "4.3.0",
  "webpack": "3.11.0"
  </code></pre>
  
  <p>Any ideas on how to resolve or to get additional logging output to track down the issue?</p>