Bump bl from 4.0.2 to 4.0.3

Bumps [bl](https://github.com/rvagg/bl) from 4.0.2 to 4.0.3.
- [Release notes](https://github.com/rvagg/bl/releases)
- [Commits](rvagg/bl@v4.0.2...v4.0.3)

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Author: dependabot[bot]