Fix icu4c issues and switch version to 63.1

icu4c-63.md

Answer from : https://stackoverflow.com/a/55828190

Solution:

1. cd to Homebrew's formula directory cd $(brew --prefix)/Homebrew/Library/Taps/homebrew/homebrew-core/Formula

2. Find desired commit (version 63 for icu4c) to checkout git log --follow icu4c.rb

3. Checkout to a new branch git checkout -b icu4c-63 e7f0f10dc63b1dc1061d475f1a61d01b70ef2cb7

4. Reinstall the library with the new version brew reinstall ./icu4c.rb

5. Switch to the reinstalled version brew switch icu4c 63.1

6. Checkout back to master git checkout master

Sources:
Homebrew install specific version of formula?

http://hanxue-it.blogspot.com/2018/08/macos-homebrew-installing-older-version-of-software.htm
https://stackoverflow.com/questions/3987683/homebrew-install-specific-version-of-formula

Thanks a lot !! this saved my life !!