docker build --no-cache --build-arg HAPROXY_BRANCH=<YOUR-TARGET-BRANCH> -t haproxy-dev .
The Dockerfile is sourced from haproxytech/haproxy-docker-alpine and modified to compile the provided dev version instead of a release.
The source code is loaded from GitHub.
You could also define a specific commit as HAPROXY_BRANCH.
The dataplane-API was stripped from the image.