webpack: Drop compression plugin's minRatio option

The default of 0.8 is just fine, no need to tweak this.

webpack.config.js

@@ -24,7 +24,6 @@ const plugins = [
 if (production) {
     plugins.unshift(new CompressionPlugin({
         test: /\.(js|html)$/,
-        minRatio: 0.9,
         deleteOriginalAssets: true
     }));
 }