Merge pull request #2720 from webcompat/greenkeeper/prettier-1.15.3

Update prettier to the latest version 🚀

Author: magsout

package.json

@@ -49,7 +49,7 @@
     "postcss-import": "^12.0.0",
     "postcss-reporter": "^6.0.0",
     "postcss-url": "^8.0.0",
-    "prettier": "1.15.2",
+    "prettier": "1.15.3",
     "stylelint": "^9.6.0",
     "stylelint-config-standard": "^18.0.0",
     "stylelint-order": "^2.0.0",