Update to rake v13
This comes standard in Ruby v2.7.2, so we don't need to install an extra gem anymore. 13.0.1 only has a few minor bug fixes: https://github.com/ruby/rake/blob/master/History.rdoc
Edited by Stan Hu
This comes standard in Ruby v2.7.2, so we don't need to install an extra gem anymore. 13.0.1 only has a few minor bug fixes: https://github.com/ruby/rake/blob/master/History.rdoc