Add deprecations warnings and failures to CI builds

[lholmquist]

Node provides flags that allow for failing when deprecated functionality is used. There are also flags for printing out deprecation warnings on functionality that will soon be deprecated. Turning on these flags will help us catch issues early that may cause failures in the future.

https://nodejs.org/api/deprecations.html#deprecations_deprecated_apis

This has more info on the --pending-deprecation and --throw-deprecation flags