chore(package): update rollup-plugin-filesize to version 8.0.1

Closes #33

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "nyc": "^13.1.0",
     "rollup": "^1.0.0",
     "rollup-plugin-babel": "^4.2.0",
-    "rollup-plugin-filesize": "^6.0.0",
+    "rollup-plugin-filesize": "^8.0.1",
     "rollup-plugin-node-resolve": "^4.0.0",
     "@babel/plugin-proposal-class-properties": "^7.2.1"
   },