np supports Node 8 but new dependency new-github-release-url supports Node 10

[brandonweiss]

I noticed the build failing on a package of mine that supports Node 8 when trying to update np from 3.1.0 to 4.0.x. The problem seems to be that although np supports Node 8 and higher new-github-release-url supports Node 10 and higher. So when Travis CI tries to test my package on Node 8 it fails trying to install devDependencies, which contains np.

Am I thinking about this wrong? It seems like np can’t depend on a package that has a stricter Node version requirement than itself?

[voxpelli]

@brandonweiss You are absolutely right I would say and I added a PR that helps test this and ensure that errors like these are caught.

I didn't include a bump of the engine version as I'm unsure how @sindresorhus would prefer to solve this.

[brandonweiss]

@sindresorhus Thanks! ❤️