Add option to disable build summary

[egrimstad]

I want to use the Github Actions summary page for something useful and to that end the output that the docker build step produces is mostly just noise. The docker action has an environment variable to disable the build summary: https://docs.docker.com/build/ci/github-actions/build-summary/#disable-job-summary

Would be nice if gha-docker had an input parameter to set the value of this environment variable.

[xamebax]

This one's now exported to our JIRA and will be followed-up.