[BUG] README may need some love on installing requirements.

[epugh]

What is the bug?

Right now the README lists out the install steps for various versions, and that takes up the bulk of the page.

Also, it doesn't reflect the 2.18 release.... It's hard to maintain.

How can one reproduce the bug?

Read the README ;-)

What is the expected behavior?

We need a more concise readme.

Do you have any additional context?

Simplify the maintence side of things!

[sstults]

Maybe just list the most recent release in the installation command? There's probably some more things we can do, but that seems like a quick win.