Bump signs_lib from 4309b35 to 87d6543

Bumps [signs_lib](https://github.com/mt-mods/signs_lib) from `4309b35` to `87d6543`.
- [Commits](mt-mods/signs_lib@4309b35...87d6543)

---
updated-dependencies:
- dependency-name: signs_lib
  dependency-type: direct:production
...

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