Update dependency prettier to v1.17.0

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change	References
prettier	devDependencies	minor	1.16.4 -> 1.17.0	homepage, source

---

Release Notes

prettier/prettier

### [`v1.17.0`](https://togithub.com/prettier/prettier/blob/master/CHANGELOG.md#​1170) [Compare Source](https://togithub.com/prettier/prettier/compare/1.16.4...1.17.0) [diff](https://togithub.com/prettier/prettier/compare/1.16.2...1.17.0) 🔗 [Release Notes](https://prettier.io/blog/2019/04/12/1.17.0.html)

---

Renovate configuration

:date: Schedule: "every weekend" (UTC).

:vertical_traffic_light: Automerge: Enabled.

:recycle: Rebasing: Whenever PR becomes conflicted, or if you modify the PR title to begin with "rebase!".

:no_bell: Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

This PR has been generated by Renovate Bot. View repository job log here.