title: Can't compile material-components with webpack-encore
body: <p><code>yarn encore dev</code> fail after setting up <code>material-components</code></p>
  
  <p>I installed <code>material-components</code> using <code>yarn add material-components-web --dev</code>  </p>
  
  <p>and then configured <code>app.js</code> like this :</p>
  
  <pre><code>/* --- CSS --- */
  import "../css/normalize.scss";
  import "material-components-web/material-components-web.scss"
  import "../css/layout.scss";
  import "../css/style.scss";
  
  /* --- RESOURCES ---*/
  import $ from "jquery";
  import * as mdc from "material-components-web";
  </code></pre>
  
  <p>When running <code>yarn encore dev</code>, I get the following error :</p>
  
  <pre><code>ERROR  Failed to compile with 1 errors                                                                                                                                                                                                                          22:30:40
  
   error  in ./node_modules/material-components-web/material-components-web.scss
  
  Module build failed (from ./node_modules/mini-css-extract-plugin/dist/loader.js):
  ModuleBuildError: Module build failed (from ./node_modules/sass-loader/lib/loader.js):
  
  @import "@material/elevation/mixins";
  ^
        File to import not found or unreadable: @material/elevation/mixins.
        in /var/www/vhosts/salon-virtuel/node_modules/@material/button/_mixins.scss (line 23, column 1)
      at runLoaders (/var/www/vhosts/salon-virtuel/node_modules/webpack/lib/NormalModule.js:301:20)
      at /var/www/vhosts/salon-virtuel/node_modules/loader-runner/lib/LoaderRunner.js:367:11
      at /var/www/vhosts/salon-virtuel/node_modules/loader-runner/lib/LoaderRunner.js:233:18
      at context.callback (/var/www/vhosts/salon-virtuel/node_modules/loader-runner/lib/LoaderRunner.js:111:13)
      at Object.render [as callback] (/var/www/vhosts/salon-virtuel/node_modules/sass-loader/lib/loader.js:52:13)
      at Object.done [as callback] (/var/www/vhosts/salon-virtuel/node_modules/neo-async/async.js:8077:18)
      at options.error (/var/www/vhosts/salon-virtuel/node_modules/node-sass/lib/index.js:294:32)
  
   @ ./assets/js/app.js 7:0-62
  
  Entrypoint app [big] = runtime.js vendors~app.js app.css app.js
  error Command failed with exit code 2.
  </code></pre>
  
  <p><strong>Imports in files :</strong></p>
  
  <p><kbd><strong>node_modules/material-components-web/material-components-web.scss</strong></kbd></p>
  
  <pre><code>@import "@material/elevation/mdc-elevation";
  </code></pre>
  
  <p><kbd><strong>node_modules/@material/elevation/mdc-elevation.scss</strong></kbd></p>
  
  <pre><code>@import "./mixins";
  @include mdc-elevation-core-styles;
  </code></pre>
  
  <p><kbd><strong>node_modules/@material/elevation/_mixins.scss</strong></kbd></p>
  
  <pre><code>@import "@material/feature-targeting/functions";
  @import "@material/feature-targeting/mixins";
  @import "@material/theme/variables";
  @import "./variables";
  </code></pre>
  
  <p>Any idea about why it's happening, and how to fix this?</p>