Show the latest API update/generation time

[arm4b]

https://api.stackstorm.com/ and https://api-unstable.stackstorm.com/ should show the latest generation time to identify how fresh or outdated the document based on StackStorm API is.

[Sheshagiri]

@armab I think it would be nice if we can show the commit of openapi.yaml on which the docs were generated instead of when the docs were generated. That way it would be easy for people to map the docs to the source.

[arm4b]

Good idea!

Having both would be even better.
Last generated <date> based on OpenAPI <sha-commit>