Ocean Beach theme is missing a dependency

[garrettjstevens]

Ocean Beach theme uses compass-vertical-rhythm:

https://github.com/KyleAMathews/typography.js/blob/33d86df7e0d7f44cd1a71c8bd8791bdb71a7ecc5/packages/typography-theme-ocean-beach/src/index.js#L5

But it's not in the dependencies:

https://github.com/KyleAMathews/typography.js/blob/33d86df7e0d7f44cd1a71c8bd8791bdb71a7ecc5/packages/typography-theme-ocean-beach/package.json#L6-L9

This causes gatsby develop to fail for me (I'm using Yarn v2):

A package is trying to access another package without the second one being listed as a dependency of the first one

Required package: compass-vertical-rhythm (via "compass-vertical-rhythm")
Required by: typography-theme-ocean-beach@npm:0.16.19 (via /path/to/.yarn/cache/typography-theme-ocean-beach-npm-0.16.19-d60d922395-2.zip/node_modules/typography-theme-ocean-beach/dist/index.js)