chore: use modern sass-loader API in webpack configs

Replace bare 'sass-loader' string with object form using
api: 'modern' to eliminate legacy JS API deprecation warnings.

Author: wangdicoder

site/config/webpack.dev.js

@@ -19,7 +19,10 @@ const devConfig = {
     rules: [
       {
         test: /.s?css$/,
-        use: ['style-loader', 'css-loader', 'sass-loader'],
+        use: ['style-loader', 'css-loader', {
+          loader: 'sass-loader',
+          options: { api: 'modern' },
+        }],
       },
     ],
   }

site/config/webpack.prod.js

@@ -10,7 +10,10 @@ const prodConfig = {
     rules: [
       {
         test: /.s?css$/,
-        use: [MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader', 'sass-loader'],
+        use: [MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader', {
+          loader: 'sass-loader',
+          options: { api: 'modern' },
+        }],
       },
     ],
   },