Bump mods/signs_lib from `1327cb2` to `aa5f865`

Bumps [mods/signs_lib](https://github.com/mt-mods/signs_lib) from `1327cb2` to `aa5f865`.
- [Release notes](https://github.com/mt-mods/signs_lib/releases)
- [Commits](https://github.com/mt-mods/signs_lib/compare/1327cb21123e89710ffcfc33a09a12912054b489...aa5f865131b61eda0e71308f1a83cd10f1ac7b31)