chore(package): update postcss-less to version 3.0.0 (#98)

Author: greenkeeper[bot]

package.json

@@ -27,7 +27,7 @@
     "mocha": "^5.2.0",
     "nyc": "^12.0.2",
     "postcss": "^7.0.1",
-    "postcss-less": "^2.0.0",
+    "postcss-less": "^3.0.0",
     "postcss-reporter": "^6.0.0",
     "stylelint": "^9.3.0"
   },