title: VueJS shows "development mode" message even with on build in production-mode
body: <p>I am having an issue getting VueJS2 (2.2.0) to run in production mode. The message &quot;You are running Vue in development mode.&quot; always shows up in the console, even though I build it with webpack in production-mode. According to <a href="https://v2.vuejs.org/v2/guide/deployment.html" rel="nofollow noreferrer">https://v2.vuejs.org/v2/guide/deployment.html</a> it should be enough to run webpack in production-mode and everything is getting minified, so webpack seems to 'know' that it is running in production mode, but vueJs doesn't play along.</p>
  <p>My webpack config looks like this:</p>
  <pre><code>let webpack = require('webpack');
  let path = require('path');
  
  module.exports = {
    entry: {
      app: './src/app.js',
        vendor: ['vue', 'axios']
      },
    output: {
      path: path.resolve(__dirname, 'public/js'),
      filename: &quot;[name].js&quot;,
      publicPath: './public',
    },
    optimization: {
      splitChunks: {
        cacheGroups: {
          vendor: {
            chunks: 'initial',
            name: 'vendor',
            test: /[\\/]node_modules[\\/]/,
          }
        }
      }
    },
    resolve: {
      alias: {
        vue: 'vue/dist/vue.js'
      }
    }
  };
  </code></pre>
  <p>In order to build my minified files for production, I run:</p>
  <pre><code>webpack --mode=production --hide-modules
  </code></pre>
  <p>I also tried manually setting the NODE_ENV to &quot;production&quot; before running webpack (4.11.1), but with no difference...</p>
  <p>What am I missing here?</p>