Support specific release composer.phar by running composer installer

Composer the latest can `self-update` specific release. It's great feature :)

Hope to support this feature in https://getcomposer.org/installer

cause I want do **one-step** install composer.phar (with more option `--install-dir`, etc. as well.)

**Added option name**

`--install-release`

**Reference(s):**

* [composer/composer GH-2522 Feature: --self-update --rollback](https://github.com/composer/composer/pull/2522)