composer インストール時にバージョンを指定する

• 2.2.4に固定したい時は下記

$ php -r "readfile('https://getcomposer.org/installer');" > composer-setup.php
$ php composer-setup.php --filename=composer --version=2.2.4
$ php -r "unlink('composer-setup.php');"
$ mv composer /usr/local/bin/composer

参考文献

• https://getcomposer.org/download/

--version
You can install composer to a specific release by using the --version option and providing a target release. Example:

php composer-setup.php --version=1.0.0-alpha8