Revert "Update composer regex to allow optional alpha/beta tags"
Revert "Update composer regex to allow optional alpha/beta tags"

This reverts commit a856d99446bdd3a435606689faf30a463d901db7.

Signed-off-by: Timothy Hitchener <bae55547f1bc62f871d56d1d41481d871519c4d3@pivotal.io>

cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack