The linked repository below contains sample scripts for Node and Bash which can be used to enable security alerts and automated security fixes in all of the repositories in a given organization.
This project is a being provided as a sample only which illustrates how to enable vulnerability alerts and enable automated security fixes in all repositories in a given organization.
Please see repo https://github.com/github/enable-security-alerts-sample for both the Node and Bash scripts, and instructions to execute them.