Add a trigger on file change

We have a non-git proprietary repository (specifically 1C configuration repository), which we are forced to use due to limitations of 1C platform. This repository is ugly and non-friendly, so we want to mirror it to a git repo in GitLab to make code reviews and other dev tasks simplier. Currently only (acceptable) way is to watch the main repo file and on it's change run a script that will mirror new commits to git repo. There is such tool in Jenkins (through a plugin), so currently we have two options - use one more tool to watch a file or switch to Jenkins CI from GitLab CI, which we already use for our other projects.

~"feature proposal"