Add documentation/examples of how to automate with GH actions

[bumblefudge]

Simplest use case is:

• on push to main affecting the source-file/md-file, render/push automatically

I tried making something from scratch to do this on /faq/ and gave up, not knowing there was already a working example of this here:

https://github.com/decentralized-identity/presentation-exchange/blob/master/.github/workflows/render-specs.yml

that I found out about here:

decentralized-identity/didcomm-messaging#196

[csuwildcat]

The render-specs.yml workflow is in this repo, so if folks clone/template with this repo, they should have it setup and running for automatic render-on-push

[bumblefudge]

My bad, will tinker and document later this month

[bumblefudge]

(src)
hehe