Docker image derived from alpine, providing openssl.
This is useful when you want to use openssl with either source or destination
files in Docker volumes, for example in post-processing
certbot certificates.
The provided build file builds this image as iay/openssl for local use.
Each push to the main branch invokes GitHub Actions to build a
multi-architecture image and pushes it to Docker Hub as ianayoung/openssl:latest.