Prevent bundling of the docs directory when publishing

[perry-mitchell]

Hi - thanks for the great library!

The bundle size pushed to npm seems a little large for what this package is providing - and things like the docs directory seem unnecessary. Would you consider a PR to remove them, and include only the necessary files via a files package.json directive?

[dance2die]

Thank you @perry-mitchell.
A PR sounds great to include necessary files only