title: Vue devServer proxy is not helping, I still get CORS error
body: <p>I'm using @vue/cli 3.x and in my vue.config.js I have this:</p>
  
  <pre><code>devServer: {
      proxy: {
        "/api": {
          ws: true,
          changeOrigin: true,
          target: "http://localhost:8080"
        }
      }
    }
  </code></pre>
  
  <p>But I keep getting CORS error:</p>
  
  <blockquote>
    <p>Access to XMLHttpRequest at '<a href="http://localhost:8080/api" rel="noreferrer">http://localhost:8080/api</a>' from origin
    '<a href="http://localhost:3000" rel="noreferrer">http://localhost:3000</a>' has been blocked by CORS policy: No
    'Access-Control-Allow-Origin' header is present on the requested
    resource.</p>
  </blockquote>
  
  <p>Any idea?</p>