* feature: Add support for github action variables * add --var flag for github variables * unitests: Updated unittests to cover vars context. * Remove syntax extension for vars and correct unit tests * Update pkg/runner/expression.go Co-authored-by: ChristopherHX <christopher.homberger@web.de> --------- Co-authored-by: kuanyong-wong-partior <kuanyong.wong@partior.com> Co-authored-by: ChristopherHX <christopher.homberger@web.de>