chore: bump @jspm/generator from 2.1.3 to 2.3.1 (#2848)

Bumps [@jspm/generator](https://github.com/jspm/generator) from 2.1.3 to 2.3.1.
- [Release notes](https://github.com/jspm/generator/releases)
- [Commits](jspm/generator@2.1.3...2.3.1)

---
updated-dependencies:
- dependency-name: "@jspm/generator"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]