GHSA-5hwf-rc88-82xm: Fickling missing RCE-capable modules in UNSAFE_IMPORTS

Fickling, a security tool that checks if pickle files (serialized Python objects) are safe, was missing three standard library modules from its blocklist of dangerous imports: `uuid`, `_osx_support`, and `_aix_support`. These modules contain functions that can execute arbitrary commands on a system, and malicious pickle files using them could bypass Fickling's safety checks and run attacker-controlled code.