Update openbazaar-beta to 2.0.15-rc1 (#4636)

Casks/openbazaar-beta.rb

@@ -1,11 +1,11 @@
 cask 'openbazaar-beta' do
-  version '2.0.14-rc1'
-  sha256 'f28b2e2e005eb1b1cc262d2826ebc28fae49d6f885d8ec5d377330f09e84c5be'
+  version '2.0.15-rc1'
+  sha256 '415c9cf4a436c86111df1befb4ffc7f676b0615ccbe79fb666631e2144bd65e0'
 
   # github.com/OpenBazaar/openbazaar-desktop was verified as official when first introduced to the cask
   url "https://github.com/OpenBazaar/openbazaar-desktop/releases/download/v#{version}/OpenBazaar#{version.major}-#{version.major_minor_patch}.dmg"
   appcast 'https://github.com/OpenBazaar/openbazaar-desktop/releases.atom',
-          checkpoint: 'a3d9a444dab82aa16bc202e77efb7d7ae8f49e503e03cf3c754d29e0265eb63a'
+          checkpoint: 'b4a15cb3b69a416f6dd8850be1d9108fe4f43179040655d7af7ca5cb904230ec'
   name 'OpenBazaar Beta'
   homepage 'https://www.openbazaar.org/'