Add 'circleci step skip-build' command
Currently it's possible to stop a job once it's started based on some conditions/logic within a step by calling `circleci step halt`. The job will stop and it's marked as successful. It's very useful to be able to to this so you can properly terminate a job based on some (complex) conditions. The build is 'successful' however, so following jobs in a workflow will be executed.
It would be great to be able to tell CircleCI to fully skip a build from a job step. Marking it as 'skipped' in the CircleCI UI and thus ignoring any other following builds or jobs in the workflows.
Add a command to tell CircleCI to fully skip the current build. I propose `circleci step skip-build` (similar to the existing `circleci step halt`).
- run: circleci step skip-build
- ... the current job to stop (not executing any following steps).
- ... to not start any following jobs or workflows for this build.
- ... to finish other parallel jobs for this build, but any following jobs won't be started.
- ... mark the build as 'skipped' for the CircleCI UI.