Publish docker image

What does this MR do?

• Publish a Docker image of the security-triage-automation tool, to make it easier to use in a standalone manner.
• Bump the version of Ruby to 3.2.2
• Monkeypatch OptionParser to allow reading commandline options from environment variables.
• Add a CHANGELOG.md file to keep track of releases.
• Update the commandline tool to output the current version of the tool, based on the most recent changelog entry.
• Add docker.yml for automatically building a new Docker image in MR pipelines and git tag pipelines
• Add upsert-git-tag.yml to automatically tag and release a new image when an MR is merged with a new changelog version.
• Set the CREATE_GIT_TAG environment variable in the project CI/CD Settings to enable the code in upsert-git-tag.yml.

What are the relevant issue numbers?

Publish security-triage-automation Docker image (gitlab-org/gitlab#424945 - closed)