AC-9720:Upgrade grunt-contrib-cssmin library (v5.0.0) to the latest version

Author: glo17680

package.json.sample

@@ -15,7 +15,7 @@
     "grunt-continue": "~0.1.0",
     "grunt-contrib-clean": "~2.0.1",
     "grunt-contrib-connect": "~4.0.0",
-    "grunt-contrib-cssmin": "~4.0.0",
+    "grunt-contrib-cssmin": "~5.0.0",
     "grunt-contrib-imagemin": "~4.0.0",
     "grunt-contrib-jasmine": "~4.0.0",
     "grunt-contrib-less": "~3.0.0",