IMPORTANT: In order for the below to work on Windows, you need to set options(url.method = "libcurl") first.
## Windows users only
options(url.method = "libcurl")
# From CRAN
source('https://callr.org/install#knitr')
# From Bioconductor
source('https://callr.org/install#limma')
# From GitHub
source('https://callr.org/install#rstudio/rmarkdown')
source('https://callr.org/install#HenrikBengtsson/R.utils@develop')
# Multiple packages from mixed sources
source('https://callr.org/install#knitr,rstudio/rmarkdown')
All dependent packages will be installed. If a requested package is already installed and up-to-date, it will not be reinstalled. All installed packages will be updated.