Bump ejs and grunt-contrib-nodeunit (#1013)

Bumps [ejs](https://github.com/mde/ejs) to 3.1.8 and updates ancestor dependency [grunt-contrib-nodeunit](https://github.com/gruntjs/grunt-contrib-nodeunit). These dependencies need to be updated together.


Updates `ejs` from 2.6.1 to 3.1.8
- [Release notes](https://github.com/mde/ejs/releases)
- [Changelog](https://github.com/mde/ejs/blob/main/CHANGELOG.md)
- [Commits](mde/ejs@v2.6.1...v3.1.8)

Updates `grunt-contrib-nodeunit` from 2.0.0 to 4.0.0
- [Release notes](https://github.com/gruntjs/grunt-contrib-nodeunit/releases)
- [Changelog](https://github.com/gruntjs/grunt-contrib-nodeunit/blob/main/CHANGELOG)
- [Commits](gruntjs/grunt-contrib-nodeunit@v2.0.0...v4.0.0)

---
updated-dependencies:
- dependency-name: ejs
  dependency-type: indirect
- dependency-name: grunt-contrib-nodeunit
  dependency-type: direct:development
...

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Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]