Important notice from Amplitude: please update to v4.1.1 or newer

[ryanashcraft]

Amplitude is encouraging all of our customers using our JavaScript SDK < v4.1.1 to update immediately in order to avoid possible data contamination. We plan to stop collecting data from older versions of the SDK in early 2019. For more context, please see this article.

This project seems to be currently using v4.1.0. Please update to the latest SDK version v4.5.0.