An in-range update of babel7 is breaking the build 🚨

## There have been updates to the *babel7* monorepo:

+ - The `devDependency` [@babel/cli](https://www.npmjs.com/package/@babel/cli) was updated from `7.7.7` to `7.8.0`.
- The `devDependency` [@babel/core](https://www.npmjs.com/package/@babel/core) was updated from `7.7.7` to `7.8.0`.
- The `devDependency` [@babel/preset-env](https://www.npmjs.com/package/@babel/preset-env) was updated from `7.7.7` to `7.8.0`.
- The `devDependency` [@babel/register](https://www.npmjs.com/package/@babel/register) was updated from `7.7.7` to `7.8.0`.

🚨 [View failing branch](https://github.com/azu/gitbook-starter-kit/compare/master...azu:greenkeeper%2Fmonorepo.babel7-20200112133918).

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

This monorepo update includes releases of one or more dependencies which all belong to the [babel7 group definition](https://github.com/greenkeeperio/monorepo-definitions).

babel7 is a devDependency of this project. It **might not break your production code or affect downstream projects**, but probably breaks your build or test tools, which may **prevent deploying or publishing**.

Status Details

- ❌ **continuous-integration/travis-ci/push:** The Travis CI build could not complete due to an error ([Details](https://travis-ci.org/azu/gitbook-starter-kit/builds/635980554?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 linked failing branch and the Travis CI build details to identify why the Babel 7.8.0 dependency updates break the build. Reproduce the failure with the updated @babel/cli, @babel/core, @babel/preset-env, and @babel/register versions, then confirm that the build passes again.

Written by the indexing model from the issue text.