fix(deps): update dependency codemirror to v5.39.2

This Pull Request updates dependency codemirror from v5.39.0 to v5.39.2

Note: This PR was created on a configured schedule ("every weekend" in timezone Europe/Paris) and will not receive updates outside those times.

Release Notes

### [`v5.39.2`](https://github.com/codemirror/CodeMirror/blob/master/CHANGELOG.md#5392-2018-07-20) [Compare Source](https://github.com/codemirror/CodeMirror/compare/5.39.0...5.39.2) ##### Bug fixes Fix issue where when you pass the document as a `Doc` instance to the `CodeMirror` constructor, the `mode` option was ignored. Fix bug where line height could be computed wrong with a line widget below a collapsed line. Fix overeager `.npmignore` dropping the `bin/source-highlight` utility from the distribution. [show-hint addon](http://codemirror.net/doc/manual.html#addon_show-hint): Fix behavior when backspacing to the start of the line with completions open. ---

This PR has been generated by Renovate Bot.

algolia / community-project-boilerplate

fix(deps): update dependency codemirror to v5.39.2 #171