Delete minishift-beta (#4051)

Casks/minishift-beta.rb

@@ -1,16 +0,0 @@
-cask 'minishift-beta' do
-  version '1.0.1'
-  sha256 '1bf40df9909a7a44fbdb0f229eaff86a803e080a365c7d05f54bf6af1c19f58d'
-
-  url "https://github.com/minishift/minishift/releases/download/v#{version}/minishift-#{version}-darwin-amd64.tgz"
-  appcast 'https://github.com/minishift/minishift/releases.atom',
-          checkpoint: '80a24dd49bb10aa5a8ef21dc492eb487f4931343224662049b2118250b4ab49a'
-  name 'Minishift'
-  homepage 'https://github.com/minishift/minishift'
-
-  binary 'minishift', target: 'minishift'
-
-  postflight do
-    set_permissions "#{staged_path}/minishift", '0755'
-  end
-end