Warnings on asset size limit

[vhscom]

Related to webpack/webpack#3486. Given this project was created for chrome extensions and has opinion to how files are chunked it seems the most appropriate place to address.

WARNING in asset size limit: The following asset(s) exceed the recommended size limit (244 KiB).
This can impact web performance.
Assets:
  vendor.js (1010 KiB)
  background.js (612 KiB)
  popup.js (302 KiB)

WARNING in entrypoint size limit: The following entrypoint(s) combined asset size exceeds the recommended limit (244 KiB). This can impact web performance.
Entrypoints:
  popup (1.29 MiB)
      vendor.js
      popup.js
  background (612 KiB)
      background.js

I'd wager most users of this project experience this issue.