Add strong suggestion to update R packages before using nfidd pkg #132
Description
A common troubleshooting error that kept several folk from jumping into to course material quickly was not necessarily having trouble installing nfidd or Stan related packages, but having other outdated packages. In these cases, having students update all their other packages or, worst case updating their entire R (which is probably good anyway), resolved several issues.
Adding a statement about updating all installed R packages may alleviate some issues:
E.g. Step 2 in Getting Started: If you already have R and R Studio installed, update all packages before continuing to install nfidd and cmdstan. (Update R if you want to be extra safe)