Bump external/fmt from e9eaa27 to 4b8e283

Bumps [external/fmt](https://github.com/fmtlib/fmt) from `e9eaa27` to `4b8e283`.
- [Release notes](https://github.com/fmtlib/fmt/releases)
- [Commits](fmtlib/fmt@e9eaa27...4b8e283)

---
updated-dependencies:
- dependency-name: external/fmt
  dependency-type: direct:production
...

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