install gapminder package

[ahmadmmohammad]

I couldn't install devtools for R v.3.1.2 because it wasn't available so I installed RV.3.6 with the latest Rtools and was able to install the devtools package. However I am getting the below error to install the gapminder package:

install.packages("devtools")
Installing package into ‘C:/Users/ahmad/Documents/R/win-library/3.6’
(as ‘lib’ is unspecified)
--- Please select a CRAN mirror for use in this session ---
trying URL 'https://cran.ma.imperial.ac.uk/bin/windows/contrib/3.6/devtools_2.3.0.zip'
Content type 'application/zip' length 350683 bytes (342 KB)
downloaded 342 KB

package ‘devtools’ successfully unpacked and MD5 sums checked

The downloaded binary packages are in
C:\Users\ahmad\AppData\Local\Temp\RtmpWYMnCJ\downloaded_packages

library(devtools)
Loading required package: usethis
install_github("jennybc/gapminder")
Skipping install of 'gapminder' from a github remote, the SHA1 (ddfe7738) has not changed since last install.
Use force = TRUE to force installation
force = TRUE

and nothing happens later