Consider only offering prebuilds for N-API v3

[dennisameling]

Summary

Since Node 8.11.2, N-API v3 has been supported. node-keytar is already built on N-API, but is still providing many prebuilds for Electron and NodeJS. Downside of this is that with every new major version release of either NodeJS or Electron, those prebuild targets have to be added.

Major libraries like sharp are now switching to N-API prebuilds only. E.g. if you compare Sharp 0.25.4 to 0.26.3, you'll see that in the newer version, only 6 prebuilds were needed, compared to 72 in the older one.

Building node-keytar for N-API is already possible today by running prebuild -t 3 -r napi.

Are you OK with switching to N-API prebuilds only, or are there reasons not to do that? I'm happy to provide a PR for it.

Motivation

Significantly reduces the amount of prebuilds that need to be generated for node-keytar.

Describe alternatives you've considered

N/A

Additional context

N/A

[shiftkey]

Are you OK with switching to N-API prebuilds only, or are there reasons not to do that? I'm happy to provide a PR for it.

I'm mostly holding off on the switch because N-API support is a recent addition - #268

As we stop supporting older versions of Node I'm 👍 to seeing when we can cutover to N-API only. Happy to review a PR and figure out when we want to make that happen.