PyICU dependency causing pip upgrade failure on macOS

[anthonydb]

Attempting to update to the latest version of agate causes an error on macOS:

FileNotFoundError: [Errno 2] No such file or directory: 'icu-config'

I may be wrong, but after a bunch of reading, it looks like the culprit is the PyICU dependency, which, according to that library's author, cannot be pip installed:

ovalhub/pyicu#141 (comment)

[tommyjcarpenter]

this is a dupe of the issue I raised last week here: #754

[anthonydb]

Generates a different error on macOS even though it has the same issue at its root.

[palewire]

This also causes install errors far far far downstream on Heroku, where the PyICU library can't compile.

https://stackoverflow.com/questions/31975668/installation-of-pyicu-on-heroku

[palewire]

My hopes are not high for heroku after reading this https://gitlab.pyicu.org/main/pyicu/-/issues/150

[jpmckinney]

I've made a commit that removes the PyICU dependency. Let me know if it works, and I'll make a release.

[palewire]

I trust you on it. I say let it rip.

[tommyjcarpenter]

is there a PR to review?

[anthonydb]

I'm still getting this error on macOS with version 1.6.2. Do you need to also specify darwin for sys_platform in setup.py?

[jpmckinney]

It will be fixed in 1.6.3 only.