Maybe it needs git to resolve the dependency?

Dockerfile

 FROM centos:centos7
 RUN yum -y update
 RUN yum -y install epel-release
-RUN yum -y install composer lighttpd lighttpd-fastcgi php-cgi
+RUN yum -y install composer lighttpd lighttpd-fastcgi php-cgi git
 COPY composer.json composer.lock /var/www/
 WORKDIR /var/www/
 RUN composer install --no-dev