Gitlab runner required help to set shm-size for docker

I am running the selenium test on docker ,

Test’s are passing if the --shm-size=2G is mentioned as show below
docker run --shm-size=2G registry.gitlab.com/xxxxxxx sh -xe script.sh

I want to set this configuration which equal’s on runner and tried this but doesn’t work
[runners.docker]
shm_size = 20000

Any suggestions are appreciated

you might try to add the following (Ibelieve this should be outside the [runners.docker] section but within the [[runners]] section:
environment = [“DOCKER_SHM_SIZE=20000”]