Bump @types/async from 3.2.20 to 3.2.21

Bumps [@types/async](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/async) from 3.2.20 to 3.2.21.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/async)

---
updated-dependencies:
- dependency-name: "@types/async"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>