Merge pull request #1707 from caskroom/cask-repair_update-sketch-beta

updated sketch-beta (3.4.4)

Casks/sketch-beta.rb

@@ -2,8 +2,10 @@ cask 'sketch-beta' do
   version '3.4.4'
   sha256 'd07b61e926a8a98f43b760fe10150aaf39ec66ad6fe370fac70fdbbb95923f1e'
 
-  # hockeyapp.net is the official download host per the vendor homepage
+  # hockeyapp.net/api/2/apps/0172d48cceec171249a8d850fb16276b was verified as official when first introduced to the cask
   url 'https://rink.hockeyapp.net/api/2/apps/0172d48cceec171249a8d850fb16276b/app_versions/164?format=zip&avtoken=1bf9ed78e68e54974eb9cc9516a216ba82c3f245'
+  appcast 'https://rink.hockeyapp.net/api/2/apps/0172d48cceec171249a8d850fb16276b',
+          checkpoint: 'c08d7f38314e84bcc3ad2c792c40aedcea49d4d4ba672817386d266efbcae4e2'
   name 'Sketch'
   homepage 'http://bohemiancoding.com/sketch/beta/'
   license :commercial