Bump grunt from 1.0.4 to 1.3.0 in /slides (#25)

Bumps [grunt](https://github.com/gruntjs/grunt) from 1.0.4 to 1.3.0.
- [Release notes](https://github.com/gruntjs/grunt/releases)
- [Changelog](https://github.com/gruntjs/grunt/blob/main/CHANGELOG)
- [Commits](gruntjs/grunt@v1.0.4...v1.3.0)

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