Add more release dates to docs

Dates pulled right out of https://github.com/saltstack/salt/tags

I've needed this info in the past so it made sense to add some more release dates. Ref #9426

Didn't go further back than 0.9.x because of some pagination weirdness on GitHub.

PS. Noticed that there are some trailing-whitespace changes by my editor as well. They should be fine.