chore(deps): update dependency gulp-babel to v8

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
gulp-babel	^5.2.1 -> ^8.0.0

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Release Notes

babel/gulp-babel (gulp-babel)

### [`v8.0.0`](https://togithub.com/babel/gulp-babel/blob/HEAD/CHANGELOG.md#800-beta2-2018-03-14) [Compare Source](https://togithub.com/babel/gulp-babel/compare/v7.0.1...v8.0.0) - **\[Fix]** Fix for `sourceMapTarget` removal in Babel v7.0.0-beta.41 ([#​149](https://togithub.com/babel/gulp-babel/pull/149)) ### [`v7.0.1`](https://togithub.com/babel/gulp-babel/compare/v7.0.0...v7.0.1) [Compare Source](https://togithub.com/babel/gulp-babel/compare/v7.0.0...v7.0.1) ### [`v7.0.0`](https://togithub.com/babel/gulp-babel/blob/HEAD/CHANGELOG.md#700-2017-08-06) [Compare Source](https://togithub.com/babel/gulp-babel/compare/v6.1.3...v7.0.0) - **\[Breaking change]** Make `babel-core` a peer dependency ### [`v6.1.3`](https://togithub.com/babel/gulp-babel/compare/v6.1.2...v6.1.3) [Compare Source](https://togithub.com/babel/gulp-babel/compare/v6.1.2...v6.1.3) ### [`v6.1.2`](https://togithub.com/babel/gulp-babel/blob/HEAD/CHANGELOG.md#612-2016-01-31) [Compare Source](https://togithub.com/babel/gulp-babel/compare/v6.1.1...v6.1.2) - **\[Fix]** Do not add `.js` extension to files without extension ([#​74](https://togithub.com/babel/gulp-babel/pull/74)) ### [`v6.1.1`](https://togithub.com/babel/gulp-babel/compare/v6.1.0...v6.1.1) [Compare Source](https://togithub.com/babel/gulp-babel/compare/v6.1.0...v6.1.1) ### [`v6.1.0`](https://togithub.com/babel/gulp-babel/compare/v6.0.0...v6.1.0) [Compare Source](https://togithub.com/babel/gulp-babel/compare/v6.0.0...v6.1.0) ### [`v6.0.0`](https://togithub.com/babel/gulp-babel/releases/tag/v6.0.0): 6.0.0 [Compare Source](https://togithub.com/babel/gulp-babel/compare/v5.3.0...v6.0.0) Upgrade to Babel 6.0.0: http://babeljs.io/blog/2015/10/29/6.0.0/

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