title: Sass Loader Error: Invalid options object that does not match the API schema
body: <p>I'm using VueJS with the framework <a href="https://vuetifyjs.com" rel="noreferrer">VuetifyJS</a> (v2.0.19). I'm getting this error after running <em>npm run serve</em>:</p>
  
  <blockquote>
    <p>Sass Loader has been initialised using an options object that does not
    match the API schema.</p>
  </blockquote>
  
  <p>What I tried:
  I've deleted the <em>node_modules</em> folder and reinstalled/updated all npm packages and node.js to the latest stable version.   </p>
  
  <p>Full error message:</p>
  
  <pre><code> error  in ./node_modules/vuetify/src/components/VRangeSlider/VRangeSlider.sass
  
  Module build failed (from ./node_modules/sass-loader/dist/cjs.js):
  ValidationError: Invalid options object. Sass Loader has been initialised using an options object that does not match the API schema.
   - options has an unknown property 'indentedSyntax'. These properties are valid:
     object { implementation?, sassOptions?, prependData?, sourceMap?, webpackImporter? }
      at validate (/home/do/Desktop/A/Projects/Ral/AppCLI3/node_modules/sass-loader/node_modules/schema-utils/dist/validate.js:50:11)
      at Object.loader (/home/do/Desktop/A/Projects/Ral/AppCLI3/node_modules/sass-loader/dist/index.js:36:28)
  
   @ ./node_modules/vuetify/src/components/VRangeSlider/VRangeSlider.sass 4:14-208 14:3-18:5 15:22-216
   @ ./node_modules/vuetify/lib/components/VRangeSlider/VRangeSlider.js
   @ ./node_modules/vuetify/lib/components/VRangeSlider/index.js
   @ ./node_modules/vuetify/lib/components/index.js
   @ ./node_modules/vuetify/lib/index.js
   @ ./src/main.js
   @ multi (webpack)-dev-server/client?http://192.168.2.115:8080/sockjs-node (webpack)/hot/dev-server.js ./src/main.js
  
   error  in ./node_modules/vuetify/src/styles/main.sass
  </code></pre>
  
  <p>My package.json:</p>
  
  <pre><code>  {
    "name": "app",
    "version": "0.1.0",
    "private": false,
    "scripts": {
      "serve": "vue-cli-service serve",
      "build": "vue-cli-service build",
      "lint": "vue-cli-service lint"
    },
    "dependencies": {
      "core-js": "^3.2.1",
      "fibers": "^4.0.1",
      "firebase": "^7.0.0",
      "material-icons": "^0.3.1",
      "register-service-worker": "^1.6.2",
      "vue": "^2.6.10",
      "vue-flickity": "^1.2.1",
      "vue-router": "^3.1.3",
      "vuetify": "^2.0.19",
      "vuex": "^3.1.1"
    },
    "devDependencies": {
      "@mdi/font": "^4.4.95",
      "@vue/cli-plugin-babel": "^3.11.0",
      "@vue/cli-plugin-eslint": "^3.11.0",
      "@vue/cli-plugin-pwa": "^3.11.0",
      "@vue/cli-service": "^3.11.0",
      "@vue/eslint-config-prettier": "^5.0.0",
      "babel-eslint": "^10.0.3",
      "eslint": "^6.5.1",
      "eslint-plugin-prettier": "^3.1.1",
      "eslint-plugin-vue": "^5.2.3",
      "material-design-icons-iconfont": "^5.0.1",
      "node-sass": "^4.12.0",
      "prettier": "1.18.2",
      "sass-loader": "^8.0.0",
      "stylus": "^0.54.7",
      "stylus-loader": "^3.0.2",
      "uglifyjs-webpack-plugin": "^2.2.0",
      "vue-cli-plugin-vuetify": "^0.6.3",
      "vue-loader": "^15.7.1",
      "vue-template-compiler": "^2.6.10",
      "vuetify-loader": "^1.3.0",
      "webpack": "^4.41.0",
      "webpack-cli": "^3.3.9"
    },
    "eslintConfig": {
      "root": true,
      "env": {
        "node": true
      },
      "extends": [
        "plugin:vue/essential",
        "@vue/prettier"
      ],
      "rules": {
        "no-console": "off"
      },
      "parserOptions": {
        "parser": "babel-eslint"
      }
    },
    "postcss": {
      "plugins": {
        "autoprefixer": {}
      }
    },
    "browserslist": [
      "&gt; 1%",
      "last 2 versions"
    ]
  }
  </code></pre>
  
  <p>How to fix this issue?</p>