Create SECURITY.md

[cshein45]

Add SECURITY.md with supported versions and vulnerability reporting process

[cshein45]

@movement-policy-service agree [company="{MovementNetworkFoundation}"]
Options:

(default - no company specified) I have sole ownership of intellectual property rights to my Submissions and I am not making Submissions in the course of work for my employer.
@movement-policy-service agree
(2023.1.5) I am making Submissions in the course of work for my employer (or my employer has intellectual property rights in my Submissions by contract or applicable law). I have permission from my employer to make Submissions and enter into this Agreement on behalf of my employer. By signing below, the defined term “You” includes me and my employer.
@dotnet-policy-service agree company="Microsoft"
Contributor License Agreement