Link to changelogs in docs instead of doing blog posts on each release

[namurphy]

It's been pretty common for us me to forget to do the blog posts for the releases. If we have a feature release cadence of ∼3–4 months, we would end up needing to do this pretty often. The blog posts from the releases often repeat information from the changelog. I'm thinking that instead of having blog posts on each release, we should link to the changelog index page such that we won't need to update the webpage with each release.