Bump eslint-plugin-jsx-a11y from 6.2.0 to 6.2.1 (#240)

Bumps [eslint-plugin-jsx-a11y](https://github.com/evcohen/eslint-plugin-jsx-a11y) from 6.2.0 to 6.2.1.
<details>
<summary>Changelog</summary>

*Sourced from [eslint-plugin-jsx-a11y's changelog](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/CHANGELOG.md).*

> 6.2.1 / 2019-02-03
> =================
> - 9980e45 [fix] Prevent Error when JSXSpreadAttribute is passed to isSemanticRoleElement
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<summary>Commits</summary>

- [`1ec0749`](infofarmer/eslint-plugin-jsx-a11y@1ec0749) 6.2.1
- [`e4c0536`](infofarmer/eslint-plugin-jsx-a11y@e4c0536) CHANGELOG for v6.2.1
- [`db0aa24`](infofarmer/eslint-plugin-jsx-a11y@db0aa24) Merge pull request [#545](https://github-redirect.dependabot.com/evcohen/eslint-plugin-jsx-a11y/issues/545) from evcohen/fix--isSemanticRoleElement
- [`4f79558`](infofarmer/eslint-plugin-jsx-a11y@4f79558) Prevent Error when JSXSpreadAttribute is passed to isSemanticRoleElement
- See full diff in [compare view](infofarmer/eslint-plugin-jsx-a11y@v6.2.0...v6.2.1)
</details>
<details>
<summary>Maintainer changes</summary>

This version was pushed to npm by [jessebeach](https://www.npmjs.com/~jessebeach), a new releaser for eslint-plugin-jsx-a11y since your current version.
</details>
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