Docs: Update outdated and vulnerable jQuery version about reswift

[DivineDominion]

@jklingen Thanks for reporting this!

Would you be up to the task of making a PR for the documentation? The template is in https://github.com/ReSwift/ReSwift/tree/master/Docs/jazzy-theme/assets/js

[jklingen]

I can offer to create a PR replacing the JS file, but I can't promise it won't break anything 😏 I don't know Jazzy and what it uses jQuery for. And I haven't been using jQuery for ages, so I am not sure what kind of changes are included in the updated versions.

But if it helps nevertheless, I'm happy to create a PR.

[mjarvis]

Its likely this is using a default theme from Jazzy, and that we can likely update jazzy / the theme, and theoretically they have updated their dependencies.