> * Can I reference the latest version, if so what would be the URL?

The latest version would be the 1.3.2 mentioned in the comments. I
don't believe Google provides a way to just get the 'latest', but you
probably wouldn't want to, because jQuery can change how some
functions work from version to version - an automatic update like this
could break your site, and it might take you some time to notice, pin
down, and debug.

It's probably safer to work with the most recent stable version and
test your code with a new version before upgrading.