fix: minimizeOptions should be query.minimize!

It's a mistake according to the doc.

Init `minimizeOptions` should be `query.minimize` rather than just query.

https://github.com/webpack/css-loader#minification

Author: JounQin

lib/processCss.js

@@ -179,7 +179,7 @@ module.exports = function processCss(inputSource, inputMap, options, callback) {
 	]);
 
 	if(minimize) {
-		var minimizeOptions = assign({}, query);
+		var minimizeOptions = assign({}, query.minimize);
 		["zindex", "normalizeUrl", "discardUnused", "mergeIdents", "reduceIdents", "autoprefixer"].forEach(function(name) {
 			if(typeof minimizeOptions[name] === "undefined")
 				minimizeOptions[name] = false;