Typescript types not correctly published to npm

[Idicious]

I noticed that the version with typescript types is published to npm, but the type files haven't been copied from the src to lib directory, which is the type root. Copying the type files is part of the prepublish script in the repo, but perhaps you use another command in the ci tooling.

In any case, to fix this, before publishing to npm the prepublish script should be run.