pandoc: migrate to Homebrew (#23520)

Casks/pandoc.rb

@@ -1,18 +0,0 @@
-cask 'pandoc' do
-  version '1.17.2'
-  sha256 'e733d3f0ecafe4fc76c503162d4a08f69a237fcb48085626a7a7a2e2da3a405f'
-
-  # github.com/jgm/pandoc was verified as official when first introduced to the cask
-  url "https://github.com/jgm/pandoc/releases/download/#{version}/pandoc-#{version}-osx.pkg"
-  appcast 'https://github.com/jgm/pandoc/releases.atom',
-          checkpoint: '1de4300533008d6ea951e33fb8acf4c69b741591d4b43fa7ad511afbbfa959b5'
-  name 'Pandoc'
-  homepage 'http://pandoc.org/'
-  license :gpl
-
-  conflicts_with formula: 'pandoc'
-
-  pkg "pandoc-#{version}-osx.pkg"
-
-  uninstall pkgutil: 'net.johnmacfarlane.pandoc'
-end

tap_migrations.json

@@ -11,6 +11,7 @@
   "go": "homebrew/core",
   "hub": "homebrew/core",
   "packer": "homebrew/core",
+  "pandoc": "homebrew/core",
   "phantomjs": "homebrew/core",
   "purescript": "homebrew/core",
   "python": "homebrew/core",