[email protected] workaround solution

for extra brotli-size build requirement ref:
siddharthkp/bundlesize#202

Author: Christopher J. Brody

package.json

@@ -84,7 +84,7 @@
     "babel-plugin-transform-object-rest-spread": "^6.23.0",
     "babel-plugin-transform-react-jsx": "^6.24.1",
     "babel-preset-env": "^1.6.1",
-    "bundlesize": "^0.17.0",
+    "bundlesize": "0.15.x",
     "chai": "^4.1.2",
     "copyfiles": "^2.0.0",
     "core-js": "^2.4.1",