Docs out of sync

[ghost]

The docs on Github and npm are out of sync.

The npm docs (still?) tell you to set the "lowercase" options property to true in order to convert the slug to lower case, even though it's actually "lower" in the code, which is confusing.

[danawoodman]

This is no longer accurate and probably should be closed

[ggarnier]

Npm docs are still outdated

[gscoon]

Yes, NPM docs need to be updated.

[Nateowami]

Just spent a good while debugging and writing an issue about how lowercase: false had no effect. The NPM docs say both lowercase and lower, but the GitHub docs all say lower, which is the correct one.

[aguyinmontreal]

still an issue in 2018