AVRO-3510: Do not hardcode the PHP Composer installer Sha384 in TravisCI#1678

thiru-mg merged 2 commits intomasterapache/avro:masterfrom

avro-3510-read-composer-installer-sha384-on-the-flyapache/avro:avro-3510-read-composer-installer-sha384-on-the-flyCopy head branch name to clipboard