Add mi beta 3.0.0b14 (#4784)

* Add mi beta 3.0.0b14

* Update mi-beta.rb

Casks/mi-beta.rb

@@ -0,0 +1,17 @@
+cask 'mi-beta' do
+  version '3.0.0b14'
+  sha256 '149c76f64963e72e569f7acf862690cf6ace8169eadd0261392d0462422161b4'
+
+  url "https://www.mimikaki.net/download/mi#{version}.dmg"
+  appcast 'https://www.mimikaki.net/download/appcast_beta.xml',
+          checkpoint: '8bdfa6654c195347c081f8e3ad37e53f9e8ede1818b902c00a6b5c1eedc03431'
+  name 'mi'
+  homepage 'https://www.mimikaki.net/download/beta.html'
+
+  depends_on macos: '>= :lion'
+
+  app 'mi.app'
+
+  zap delete: '~/Library/Caches/net.mimikaki.mi',
+      trash:  '~/Library/Preferences/net.mimikaki.mi.plist'
+end