title: Fail to install packages in RStudio
body: <p>I want to install package arulesViz but RStudio returned me this:</p>
  <pre><code>Warning in install.packages :
    unable to access index for repository https://cran.rstudio.com/src/contrib:
    cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'
  WARNING: Rtools is required to build R packages but is not currently installed. Please download and install the appropriate version of Rtools before proceeding:
  
  https://cran.rstudio.com/bin/windows/Rtools/
  Installing package into ‘C:/Users/Jacque de l'est/Documents/R/win-library/4.1’
  (as ‘lib’ is unspecified)
  Warning in install.packages :
    unable to access index for repository https://cran.rstudio.com/src/contrib:
    cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'
  Warning in install.packages :
    package ‘arulesViz’ is not available for this version of R
  
  A version of this package for your version of R might be available elsewhere,
  see the ideas at
  https://cran.r-project.org/doc/manuals/r-patched/R-admin.html#Installing-packages
  Warning in install.packages :
    unable to access index for repository https://cran.rstudio.com/bin/windows/contrib/4.1:
    cannot open URL 'https://cran.rstudio.com/bin/windows/contrib/4.1/PACKAGES'
  </code></pre>
  <p>How to solve this?</p>