Centos/mysql-57-centos7:latest - CentOS Root access?

While using CI/CD feature on Gitlab with centos/mysql-57-centos7:latest, when I install

yum install -y https://kojipkgs.fedoraproject.org//packages/zlib/1.2.11/19.fc30/x86_64/zlib-1.2.11-19.fc30.x86_64.rpm

I get error

ovl: Error while doing RPMdb copy-up:
[Errno 13] Permission denied: '/var/lib/rpm/Name'
You need to be root to perform this command.

How do I get root access on this image?