Update dependency grunt-contrib-concat to v0.5.1

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change	References
grunt-contrib-concat	devDependencies	minor	0.3.0 -> 0.5.1	source

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Release Notes

gruntjs/grunt-contrib-concat

### [`v0.5.1`](https://togithub.com/gruntjs/grunt-contrib-concat/compare/v0.5.0...v0.5.1) [Compare Source](https://togithub.com/gruntjs/grunt-contrib-concat/compare/v0.5.0...v0.5.1) ### [`v0.5.0`](https://togithub.com/gruntjs/grunt-contrib-concat/compare/v0.4.0...v0.5.0) [Compare Source](https://togithub.com/gruntjs/grunt-contrib-concat/compare/v0.4.0...v0.5.0)

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