[R] How to install packages from GitHubb

[Patrick Connolly]

R-3.4.1

Running the train function from the latest version of the caret
package on CRAN fails with this message:

 unable to find variable "optimismBoot" 
The purported workaround is to use
devtools::install_github('topepo/caret/pkg/caret') to get  the development version.

However, that evidently has the same problem with southern hemisphere
timezones that install.packages() does -- via download.packages().
i.e. it hangs.  The workaround with that one is to use method =
"internal". What is the  equivalent for install_github()?

TIA
-- 
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.   
   ___    Patrick Connolly   
 {~._.~}                   Great minds discuss ideas    
 _( Y )_  	         Average minds discuss events 
(:_~*~_:)                  Small minds discuss people  
 (_)-(_)  	                      ..... Eleanor Roosevelt
	  
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.