Add new GitLab Runner CI Environment Variable to indicate if code in build is GPG signed
Description
GitLab auto injects many environment variables into GitLab CI runner to indicate what the commit SHA, branch, tag, and many other items about what code is running in a particular GitLab CI job. Given that commits can be GPG signed, it would be nice if a new environment variable was added to indicate if the commit was GPG signed for easy reference within a build.
As a note, I realize that it is somewhat trivial to just write some additional code to leverage git commands to obtain this information, but it would be nice if this was already available to you instead of having to do this yourself.
Proposal
Add a new GitLab CI Environment Variable such as CI_COMMIT_GPG_SIGNED to be either true or false which would indicate if the commit that is checked out within the build was GPG Signed.
It would also may be a good idea to include another environment variable for CI_COMMIT_AUTHOR. While there is GITLAB_USER_ID, GITLAB_USER_EMAIL, GITLAB_USER_LOGIN and GITLAB_USER_NAME these variables tie back to who executes a CI pipeline / job which could be different than the commit author.