Undocumented version 0.4.2 does not work with Node 10

[stevelove]

https://github.com/4Catalyzer/graphql-validation-complexity/blob/3f4164b6608a1bcb6387fc330d89ee56c1ee0fcd/package.json#L3

Hello, thanks for this useful package. I wanted to point out that there does not seem to be a release page associated with the latest 0.4.2 version number. This line appears to break in Node 10.

selectionSet.selections.flatMap is not a function

The breaking change seems to have been introduced in 0.4.0. It would be helpful for others if such changes were documented on the release page.