chore(package): update promise-polyfill to version 7.0.0

package.json

@@ -65,7 +65,7 @@
     "modularscale-sass": "^3.0.3",
     "node-sass": "^4.7.2",
     "postcss-loader": "^2.0.8",
-    "promise-polyfill": "^6.0.2",
+    "promise-polyfill": "^7.0.0",
     "sass-loader": "^6.0.6",
     "style-loader": "^0.19.0",
     "stylelint": "^8.3.0",