rake 12.3.2 on Ruby Gems

What's Changed

Add alias prereqs. by @take-cheeze in #268
Fix JRuby detection on JRuby 9.2 in cpu_counter.rb by @jeremyevans in #265
Fix a typo in lib/rake/application.rb by @felixonmars in #276
Remove trailing extension name by @zhustec in #275
Use Ruby 2.2.10, 2.3.8, 2.4.5, and 2.5.3 by @aycabta in #278
fix errors in rubocop by @colby-swandale in #282
add binstubs for bundler, rake, rodc and rubocop by @colby-swandale in #280
add rubocop section to CONTRIBUTING.rdoc by @colby-swandale in #285
Rework the error message that tells users to list the tasks with rake --tasks by @colby-swandale in #287
update latest jruby version in travis by @colby-swandale in #290
fix links to rake resources not showing on Github by @colby-swandale in #288
Improve multitask performance by @jsm in #273
Update jruby to the latest version in travis by @colby-swandale in #291
run coveralls only when COVERALLS env var is present by @colby-swandale in #289
Improve running test instructions and denote commands with $ by @colby-swandale in #295
Update public clone URL to use https by @colby-swandale in #294
Rdoc improvements by @colby-swandale in #293
Fixed test fails caused by 2.6 warnings by @hsbt in #297

Full Changelog: v12.3.1...v12.3.2