icu4c updates break brand new GDK installations

Overview

icu4u had been upgraded to 70.1 yesterday, which breaks a brand new gdk installation.

Temporary solution:

# Intel
cd $(brew --prefix)/Homebrew/Library/Taps/homebrew/homebrew-core/Formula
# M1
cd $(brew --prefix)/Library/Taps/homebrew/homebrew-core/Formula

git checkout -b icu4c-69 c278d3dc42a6aac6ad7a46bd7d638c305364a888

brew reinstall ./icu4c.rb

brew info icu4c # Make sure it's 69.1

brew pin icu4c

git checkout master