The https://github.com/NARKOZ/gitlab tool is quite handy if you don't want to craft your GitLab API queries by hand with curl:

while IFS="|" read -r name access_level id ; do
  echo "$name($id) = $access_level"
done < <(gitlab group_members --json $GROUP_NAME \
    | jq -r '.result[]|[.name,.access_level,.id|tostring]|join("|")'
    )