Remove deprecated library calls

[avahoffman]

Noticed sometimes we are loading more packages than needed, eg.

library(knitr)
library(readr)
library(dplyr)
library(tidyverse)

We don't need library(readr); library(dplyr) since they load with tidyverse

[carriewright11]

Can keep track of checking with this:

• Intro
• RStudio
• Basic R
• Reproducibility
• Data Input
• Subsetting
• Summarization (currently load dplyr in lecture could do tidyverse - lab is just tidyverse)
• Data classes (has extra in the lab currently)
• Data cleaning (could remove stringr loading from lecture)
• Manipulating (could simplify it in the lab - is readr, dplyr, tidyr)
• Esquisse (load dplyr in lecture and lab but could change out for tidyverse)
• Data viz (load ggplot2 in lecture but could just do tidyverse)
• Factors (could simplify lab to just tidyverse)
• Statistics (could switch out dplyr for tidyverse in lab)
• Data Output (could change out the general output example to be tidyverse instead of readr)
• Functions (could just be tidyverse for the lab)

[avahoffman]

@carriewright11 thanks for doing the sleuthing for this one!