title: Unable to download 'blotter' package
body: <p>I'm currently running on MacOS Sierra, 10.12.6 and I'm running Rstudio Version 1.2.5033.</p>
  
  <p>I'm working on a project that requires the use of the 'quantstrat' package. </p>
  
  <p>I've been trying to install 'quantstrat' package using </p>
  
  <p>"devtools::install_github("braverock/quantstrat")"</p>
  
  <p>and I'm constantly getting this error. </p>
  
  <p>"Downloading GitHub repo braverock/quantstrat@master
  Skipping 1 packages not available: blotter
  Installing 4 packages: blotter, FinancialInstrument, foreach, iterators
  Installing packages into ‘/Library/Frameworks/R.framework/Versions/3.6/Resources/library’
  (as ‘lib’ is unspecified)
  Error: Failed to install 'quantstrat' from GitHub:
    (converted from warning) package ‘blotter’ is not available (for R version 3.6.3)"</p>
  
  <p>I've tried upgrading my version of Rstudio and find alternative sources to download 'blotter' but I'm still unable to do so. </p>
  
  <p>Anyone has any idea?</p>