Merge pull request #149 from developit/greenkeeper/pretty-bytes-5.1.0

Update pretty-bytes to the latest version 🚀

package.json

@@ -48,7 +48,7 @@
     "cssnano": "^3.10.0",
     "es6-promisify": "^6.0.0",
     "gzip-size": "^4.1.0",
-    "pretty-bytes": "^4.0.2",
+    "pretty-bytes": "^5.1.0",
     "regenerator-runtime": "^0.11.1",
     "rollup": "0.59.3",
     "rollup-plugin-buble": "^0.19.2",