build(deps): Bump external/Phi from 4787424 to 0a7a621

Bumps [external/Phi](https://github.com/AMS21/Phi) from `4787424` to `0a7a621`.
- [Commits](AMS21/Phi@4787424...0a7a621)

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

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