Update tubalmartin/cssmin to v3.0.0

Author: sambolek

composer.json

@@ -43,7 +43,7 @@
         "monolog/monolog": "^1.17",
         "oyejorge/less.php": "~1.7.0",
         "pelago/emogrifier": "0.1.1",
-        "tubalmartin/cssmin": "2.4.8-p10",
+        "tubalmartin/cssmin": "3.0.0",
         "magento/magento-composer-installer": ">=0.1.11",
         "braintree/braintree_php": "3.7.0",
         "symfony/console": "~2.3, !=2.7.0",

composer.lock

@@ -5,7 +5,7 @@
  */
 namespace Magento\Framework\Code\Minifier\Adapter\Css;
 
-use CSSmin as CssMinLibrary;
+use tubalmartin\CssMin\Minifier as CssMinLibrary;
 use Magento\Framework\Code\Minifier\AdapterInterface;
 
 /**
@@ -35,12 +35,12 @@ public function __construct(CssMinLibrary $cssMinifier)
     /**
      * Get CSS Minifier
      *
-     * @return \CSSMin
+     * @return CssMinLibrary
      */
     private function getCssMin()
     {
-        if (!($this->cssMinifier instanceof \CSSMin)) {
-            $this->cssMinifier = new \CSSmin(false);
+        if (!($this->cssMinifier instanceof CssMinLibrary)) {
+            $this->cssMinifier = new CssMinLibrary(false);
         }
         return $this->cssMinifier;
     }

lib/internal/Magento/Framework/Code/Minifier/Adapter/Css/CSSmin.php

@@ -9,7 +9,7 @@ class CssMinTest extends \PHPUnit_Framework_TestCase
 {
     public function testMinify()
     {
-        $cssMinMock = $this->getMockBuilder(\CSSmin::class)
+        $cssMinMock = $this->getMockBuilder(\tubalmartin\CssMin\Minifier::class)
             ->disableOriginalConstructor()
             ->getMock();
         $cssMinAdapter = new \Magento\Framework\Code\Minifier\Adapter\Css\CSSmin($cssMinMock);