build(deps-dev): bump conventional-changelog from 2.0.1 to 3.1.21

Bumps [conventional-changelog](https://github.com/conventional-changelog/conventional-changelog) from 2.0.1 to 3.1.21.
- [Release notes](https://github.com/conventional-changelog/conventional-changelog/releases)
- [Commits](https://github.com/conventional-changelog/conventional-changelog/compare/conventional-changelog@2.0.1...conventional-changelog@3.1.21)

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