Install the openSSL version of cURL on Mac

Recently, I needed to update my cURL to run apple push notification api but it depends on HTTP/2 protocol which my cURL is not supported.

I'll go straight to the point: Homebrew team remove all options from homebrew core.

To switch:

    $ brew upgrade
    $ brew uninstall curl
    $ brew install curl-openssl
    $ echo 'export PATH="/usr/local/opt/curl-openssl/bin:$PATH"' >> ~/.zshrc