Update dependency grunt to ^1.6.1

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
grunt (source)	^1.6.0 -> ^1.6.1

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Release Notes

gruntjs/grunt

### [`v1.6.1`](https://togithub.com/gruntjs/grunt/releases/tag/v1.6.1) [Compare Source](https://togithub.com/gruntjs/grunt/compare/v1.6.0...v1.6.1) - Changelog updates [`72f6f03`](https://togithub.com/gruntjs/grunt/commit/72f6f03) - Merge pull request [#​1755](https://togithub.com/gruntjs/grunt/issues/1755) from gruntjs/rm-dep [`8d4c183`](https://togithub.com/gruntjs/grunt/commit/8d4c183) - Add recursive [`1c7d483`](https://togithub.com/gruntjs/grunt/commit/1c7d483) - Merge pull request [#​1756](https://togithub.com/gruntjs/grunt/issues/1756) from gruntjs/downgrade-glob [`2d4fd38`](https://togithub.com/gruntjs/grunt/commit/2d4fd38) - Downgrade glob [`902db7c`](https://togithub.com/gruntjs/grunt/commit/902db7c) - Fix syntax [`494f243`](https://togithub.com/gruntjs/grunt/commit/494f243) - remove mkdirp [`b01389e`](https://togithub.com/gruntjs/grunt/commit/b01389e) - remove dep on rimraf and mkdirp [`0072510`](https://togithub.com/gruntjs/grunt/commit/0072510)

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Configuration

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