phonenumber panics on parsing crafted RF3966 inputs

phonenumber is a library for parsing, formatting and validating international phone numbers. Prior to versions `0.3.3+8.13.9` and `0.2.5+8.11.3`, the phonenumber parsing code may panic due to a panic-guarded out-of-bounds access on the phonenumber string. In a typical deployment of `rust-phonenumber`, this may get triggered by feeding a maliciously crafted phonenumber over the network, specifically the string `.;phone-context=`. Versions `0.3.3+8.13.9` and `0.2.5+8.11.3` contain a patch for this issue. There are no known workarounds.