刚刚学习用R绘制图 但是REmap怎么都安装不上
> library(devtools)
> install_github('lchiffon/REmap')
Skipping install of 'REmap' from a github remote, the SHA1 (7eabe6f7) has not changed since last install.
  Use `force = TRUE` to force installation
上网查了好久 感觉跟其他人的都不太一样 有人碰到这种吗 该怎么解决 求大神指教