Installation of Gitlab-Runner with Helm and bind to a local volume

I would like to bind a specific local directory as a volume to be used by Gitlab-Runner.
Usually to deploy the runner on the machine, I use the command:
helm upgrade --install --namespace gitlab-runner NAME -f PATH/values.yaml gitlab/gitlab-runner

In the machine, there is a dedicated space to be used by gitlab-runner so it could place artifacts to be shared among jobs on a running pipeline.

The closer I got to a solution is by doing what is described on this link, but I could not understand how to update the toml file of an already helm-deployed gitlab-runner.

The default deployment through Helm ends up in a volume that has a limited disk space and that leads to sudden failure of the pod that runs the pipeline job. That happens when the job/pipeline deals with large artifacts.

Could you give me some directions on how to point the desired volume to be used by gitlab-runner deployed by helm?