Below are my build instructions for GnuPG 2.2.17, released on July 12th, 2018. These instructions are built for a headless Centos 7 LTS server (specificaly the openshift/base-centos7 docker image).
You use the below install script to install GnuPG 2.2.x by running the following commands:
# if you are root in a docker image:
curl -OL "https://gist.githubusercontent.com/justyns/79e7e8a0750abb609a05fca50956e4a3/raw/1ca349eaa93247a18047416a44c05480669f5d86/install-gnupg22.shsh" && bash ./install-gnupg22.sh