Should we pin against a specific Node version?

[glasserc]

nodejs/node@3e0709cf5e landed in Node v10.8.1. We pin to Node v10 but not with any more specificity than that. This broke a test. The fix is easy but it raises the question of whether we should pin the Node version more tightly so that these changes are at least made explicit.

My personal opinion could go either way on this. It was a minor, cosmetic feature that broke and the tests caught it. On the other hand, we do have control over what version of Node we are using and we could justifiably pin the CI to whatever we use in prod.