Bump grunt from 0.4.5 to 1.3.0 in /tests/dummy

Bumps [grunt](https://github.com/gruntjs/grunt) from 0.4.5 to 1.3.0.
- [Release notes](https://github.com/gruntjs/grunt/releases)
- [Changelog](https://github.com/gruntjs/grunt/blob/main/CHANGELOG)
- [Commits](gruntjs/grunt@v0.4.5...v1.3.0)

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Author: dependabot[bot]