Include easy module about mapping using usmap package

[avahoffman]

https://jtr13.github.io/cc19/different-ways-of-plotting-u-s-map-in-r.html

usmap is really nice. Something like this could be really great.

wa_dat <- countypop %>% filter(abbr == "WA")
plot_usmap(data = wa_dat,
           values = "pop_2022",
           include = c("WA")) +
  scale_fill_continuous() +
  theme(legend.position = "right")

[avahoffman]

Redundant with #147