Quickstart test

[Sanaz11-3]

Test code snippets in quickstart to make sure they can be run correctly!

[emilydolson]

It was easier to make the change and show you than to explain over text how to make it. Take a look at this diff to see what I did: https://github.com/emilydolson/phylotrackpy/pull/80/files/569a8a14c707b46e214ad0a9370b0ea62c515f96..b44ecac5d58b7bf4aae9756f35931b9962dc978a

Summary:

• The added dependency was only supposed to be in test/requirements.txt, so I removed it from everywhere else
• Added a line to .github/workflows/ci.yml that tells GitHub Actions to install everything in test/requirements.txt when it runs tests
• Things will get hard to keep track of if we have a bunch of extra copies of the docs directory floating around, so I removed the other ones you added (they were also causing errors)
• It turns out the thing that I thought would fix the wheels didn't work. I had to do a slightly more complicated file path fix instead.

Now I think I've got all of the GitHub actions related problems fixed except on with Python 3.8. However, it looks like there are still some issues in the new tests (possibly related to filepaths?). Can you see if you can fix them?