Breaking change in v1.10.0+

[ljharb]

psl v1 doesn't have an engines field, which means it supports all versions of node.

v1.9 and below worked fine in node <= 4, but v1.10.0 contains untranspiled spread syntax and const/lets, and thus breaks in node 4 and below. Can you restore that support in a v1? It's fine to publish a v2 that drops it explicitly after that, of course :-)

(i'd also suggest expanding the CI matrix to include every supported node version, not just down to v8)