An in-range update of @types/prettier is breaking the build 🚨

Nobody has claimed this yet.

## The dependency [@types/prettier](https://github.com/DefinitelyTyped/DefinitelyTyped) was updated from `1.16.4` to `1.18.0`.

🚨 [View failing branch](https://github.com/linkedin/opticss/compare/master...linkedin:greenkeeper%2Fdefault%2F%40types%2Fprettier-1.18.0).

This version is **covered** by your **current version range** and after updating it in your project **the build failed**.

@types/prettier is a direct dependency of this project, and **it is very likely causing it to break**. If other packages depend on yours, this update is probably also breaking those in turn.

Status Details

- ❌ **continuous-integration/travis-ci/push:** The Travis CI build failed ([Details](https://travis-ci.org/linkedin/opticss/builds/561117470?utm_source=github_status&utm_medium=notification)).

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FAQ and help

There is a collection of [frequently asked questions](https://greenkeeper.io/faq.html). If those don’t help, you can always [ask the humans behind Greenkeeper](https://github.com/greenkeeperio/greenkeeper/issues/new).

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Your [Greenkeeper](https://greenkeeper.io) Bot :palm_tree:

Start with the Greenkeeper failing branch and the linked Travis CI build to identify the exact failure after @types/prettier changed from 1.16.4 to 1.18.0. Inspect the project's dependency declaration and CI output; the work is done when the dependency update no longer breaks the build.

Written by the indexing model from the issue text.