GHSA-3fg9-hcq5-vxrc: iana-time-zone vulnerable to use after free in MacOS / iOS implementation

In iana-time-zone v0.1.43 a use-after-free bug in the MacOS / iOS implementation was introduced.

The copied system time zone was released before its name was copied. If the system time zone was changed between the call of CFRelease and str::to_owned(), random memory would be copied.