title: webpack 4 gives background: url([object Module]) as bg image
body: <p>I'm having issues with setting up web-pack 4 and svg-sprite-loader to render svg icons as background images. I was following these instructions from official docs for svg-sprite-loader (<a href="https://github.com/kisenka/svg-sprite-loader/tree/master/examples/extract-mode" rel="noreferrer">https://github.com/kisenka/svg-sprite-loader/tree/master/examples/extract-mode</a>).</p>
  
  <p>I have successfully managed to create sprite.svg file in my dist folder and use it as reference for my use tags inside of html. However, i was also trying to use svg icons from my src/images/icons folder for a background image like this:</p>
  
  <pre><code>background: url('../images/icons/upload_icon.svg') 10% 50% no-repeat;
  </code></pre>
  
  <p>when doing this, webpack compiles correctly, but creates this in dist css file:</p>
  
  <pre><code>background: url([object Module]) 10% 50% no-repeat;
  </code></pre>
  
  <p>Any help would be great.</p>
  
  <p>here is my webpack config file:</p>
  
  <pre><code>const path = require("path");
  const webpack = require("webpack");
  const HtmlWebpackPlugin = require("html-webpack-plugin");
  const MiniCssExtractPlugin = require("mini-css-extract-plugin");
  const CleanWebpackPlugin = require("clean-webpack-plugin");
  const SpriteLoaderPlugin = require("svg-sprite-loader/plugin");
  
  module.exports = {
    mode: "development",
    devtool: "source-map",
    output: {
      filename: "bundle.js",
      path: path.resolve(__dirname, "dist")
    },
    module: {
      rules: [
        {
          test: /\.js$/,
          exclude: /node_modules/,
          use: {
            loader: "babel-loader",
            options: {
              sourceMap: true
            }
          }
        },
        {
          // scss configuration
          test: /\.scss$/,
          use: [
            MiniCssExtractPlugin.loader,
            {
              loader: "css-loader"
            },
            {
              loader: "postcss-loader"
            },
            {
              loader: "sass-loader",
              options: {
                sourceMap: true
              }
            }
          ]
        },
        {
          // html configuration
          test: /\.html$/,
          use: {
            loader: "html-loader"
          }
        },
        {
          // images configuration
          test: /\.(jpg|jpeg|gif|png|woff|woff2)$/,
          use: [
            {
              loader: "file-loader",
              options: {
                name: "[path][name].[ext]"
              }
            }
          ]
        },
        {
          test: /\.svg$/,
          use: [
            {
              loader: "svg-sprite-loader",
              options: {
                extract: true,
                spriteFilename: "sprite.svg"
              }
            }
          ]
        }
      ]
    },
    plugins: [
      // all plugins used for compiling by webpack
      new CleanWebpackPlugin(),
      new HtmlWebpackPlugin({
        title: "Style Guide",
        template: path.resolve(__dirname, "src", "index.html")
      }),
      new MiniCssExtractPlugin({
        filename: "app.css"
      }),
      new SpriteLoaderPlugin()
    ]
  };
  </code></pre>