Start using github security advisories

[Brad Bishop]

On Wed, 2021-10-27 at 18:29 +0000, Mihm, James wrote:
> Brad or Andrew, Can we proceed with the creation of security
> repository so that we can run a couple of trials on security issues?

Hi James, thanks for the ping.

The only reason I haven't already done this was this comment from Bruce:

> > 
> > I believe we want to make sure that none of security advisories
> > get sent to Discord, wouldn't want to accidentally be going to
> > something like #gh-issues.

This was a good point and I'm not sure what to do about it.

-brad