Change puppeteer to peer dependency?

[peterjosling]

This package specifies puppeteer ^1.12.2 as a dependency, which is a version that is pinned to Chrome 73. As this is a dependency of the package, there's no way to specify a different Chrome version.

Changing puppeteer to be a peer dependency would allow users of the package to specify their own version of puppeteer and be in control of the version of Chrome that gets used.

[dferber90]

Thanks for the hint @peterjosling!

iirc, the puppeteer api had a breaking change. If we make it a peer dep, we should update our puppeteer usage to ensure we can support the latest version (and update the readme/install instructions)