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

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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)

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