ipatool 2.4.0 violates Acceptable Formulae

[zhangyoufu]

Per Source availability and licences:

• It must either build from source or install portable, platform-independent output such as Java bytecode.
• Proprietary or platform-specific binary-only software belongs in a cask.
• A core formula must not depend on a cask, proprietary software or a runtime step that automatically installs either one.

In ipatool 2.4.0, to workaround Apple authentication limitation, the author of ipatool merged a change, that uses unicorn (downloaded from PyPI) to load and execute some Apple proprietary binaries (downloaded from Apple CDN) to generate a signature.

It's a clever hack. All runtime downloaded files has checksum. I appreciate author's effort on the workaround. But it may violates homebrew-core policy.