Add Skype 7.59.37 as skype7 (#4829)

Casks/skype7.rb

@@ -0,0 +1,22 @@
+cask 'skype7' do
+  version '7.59.37'
+  sha256 '5d5d6811dcb0727c478d198cb24b99317dd10db0e55d81601d77285434f8cf1d'
+
+  url "https://download.skype.com/macosx/bf9ccdd6b5b079049ff5a87419033ce3/Skype_#{version}.dmg"
+  name 'Skype'
+  homepage 'https://www.skype.com/en/get-skype/'
+
+  auto_updates true
+  conflicts_with cask: 'skype'
+
+  app 'Skype.app'
+
+  zap trash: [
+               '~/Library/Application Support/Skype',
+               '~/Library/Caches/com.plausiblelabs.crashreporter.data/com.skype.skype',
+               '~/Library/Caches/com.skype.skype',
+               '~/Library/Preferences/com.skype.skype.plist',
+               '~/Library/Preferences/com.skype.skypewifi.plist',
+               '~/Library/Saved Application State/com.skype.skype.savedState',
+             ]
+end