Patch - Build: Bump grunt-contrib-cssmin to v5.0.0 (#2481)

Patch - CSS code optimization and minification - Bump grunt-contrib-cssmin to v5.0.0

Port of wet-boew/wet-boew#9902's build change.

Author: EricDunsworth

package-lock.json

@@ -36,7 +36,7 @@
     "grunt-contrib-connect": "^3.0.0",
     "grunt-contrib-copy": "^1.0.0",
     "grunt-contrib-csslint": "~2.0.0",
-    "grunt-contrib-cssmin": "^3.0.0",
+    "grunt-contrib-cssmin": "^5.0.0",
     "grunt-contrib-htmlmin": "^3.1.0",
     "grunt-contrib-uglify": "^5.2.2",
     "grunt-contrib-watch": "^1.1.0",