Late the party but I figured this out today after digging around.
#install.packages("pheatmap")
library(pheatmap)
##install qiimer from https://cran.r-project.org/src/contrib/Archive/qiimer/
library(qiimer)
#install.packages("remotes")
library(remotes)
##install biom
library("devtools")
#devtools::install_github("joey711/biom")
##install Tax4Fun using remotes
#install.packages(remotes)
#remotes::install_github("nick-youngblut/Tax4Fun")
library(Tax4Fun)