Add definition for Ruby 2.4.4

https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-4-4-released/

share/ruby-build/2.4.4

+install_package "openssl-1.1.0g" "https://www.openssl.org/source/openssl-1.1.0g.tar.gz#de4d501267da39310905cb6dc8c6121f7a2cad45a7707f76df828fe1b85073af"  mac_openssl --if has_broken_mac_openssl
+install_package "ruby-2.4.4" "https://cache.ruby-lang.org/pub/ruby/2.4/ruby-2.4.4.tar.bz2#45a8de577471b90dc4838c5ef26aeb253a56002896189055a44dc680644243f1" ldflags_dirs standard verify_openssl