What would you like to be added:
GitHub has a [security policy](https://github.com/moby/moby/security/policy) page that uses a SECURITY.md file from the repository to show the project's security policy.
Why is this needed:
Adding this file makes it easier for security researchers to learn about the correct place to report a vulnerability in the [Moby](https://github.com/moby/moby) project.
Signed-off-by: Andrea <crypto.andrea@protonmail.ch>
