Bump 3pp/async from 3480a3e to dbf40e6

Bumps [3pp/async](https://github.com/eerimoq/async) from `3480a3e` to `dbf40e6`.
- [Release notes](https://github.com/eerimoq/async/releases)
- [Commits](eerimoq/async@3480a3e...dbf40e6)

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