Auto merge of #2712 - rust-lang:renovate/prettier-2.x, r=Turbo87

Update dependency prettier to v2.1.0

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [prettier](https://prettier.io) ([source](https://togithub.com/prettier/prettier)) | devDependencies | minor | [`2.0.5` -> `2.1.0`](https://renovatebot.com/diffs/npm/prettier/2.0.5/2.1.0) |

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### Release Notes

<details>
<summary>prettier/prettier</summary>

### [`v2.1.0`](https://togithub.com/prettier/prettier/blob/master/CHANGELOG.md#&#8203;210)

[Compare Source](https://togithub.com/prettier/prettier/compare/2.0.5...2.1.0)

[diff](https://togithub.com/prettier/prettier/compare/2.0.5...2.1.0)

🔗 [Release Notes](https://prettier.io/blog/2020/08/24/2.1.0.html)

</details>

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Author: bors