deps: bump typedoc from 0.28.19 to 0.28.20

Bumps [typedoc](https://github.com/TypeStrong/TypeDoc) from 0.28.19 to 0.28.20.
- [Release notes](https://github.com/TypeStrong/TypeDoc/releases)
- [Changelog](https://github.com/TypeStrong/typedoc/blob/master/CHANGELOG.md)
- [Commits](TypeStrong/typedoc@v0.28.19...v0.28.20)

---
updated-dependencies:
- dependency-name: typedoc
  dependency-version: 0.28.20
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]