Builds a Docker image for tags starting with 'v'
The image repository name is defined by environment variable DOCKER_REPO, which
defaults to: lightninglabs/loop
To override it, if you want to publish the image to your own DockerHub account,
define a Github Actions secret named DOCKER_REPO with the full image repo name
such as: <docker_user>/loop
To make initial triage easier and nudge people into reading the
documentation and gathering information before submitting an issue, we
add three issue templates: bug reports, feature requests and "other".
