Bump extern/ersem from a2429e2 to 8510fbf (#14)

Bumps [extern/ersem](https://github.com/pmlmodelling/ersem) from `a2429e2` to `8510fbf`.
- [Release notes](https://github.com/pmlmodelling/ersem/releases)
- [Commits](pmlmodelling/ersem@a2429e2...8510fbf)

---
updated-dependencies:
- dependency-name: extern/ersem
  dependency-type: direct:production
...

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