Installation instructions install an old version of rvsearch

[rbowru]

Hello,

I was following the instillation instructions listed here, and I noticed that the install finished with rvsearch 0.3.3 instead of the most up to date version:
https://california-planet-search.github.io/rvsearch/index.html

It might help new users if you added a line in the documentation to run an upgrade on rvsearch so that new users are starting on the current version:
pip install --upgrade rvsearch

Thank you!