Cask: audit: Do not require appcast on GitHub releases

Library/Homebrew/cask/audit.rb

@@ -310,10 +310,6 @@ module Cask
       add_appcast = "please add an appcast. See https://github.com/Homebrew/homebrew-cask/blob/HEAD/doc/cask_language_reference/stanzas/appcast.md"
 
       case cask.url.to_s
-      when %r{github.com/([^/]+)/([^/]+)/releases/download/(\S+)}
-        return if cask.version.latest?
-
-        add_error "Download uses GitHub releases, #{add_appcast}"
       when %r{sourceforge.net/(\S+)}
         return if cask.version.latest?
 

Library/Homebrew/test/cask/audit_spec.rb

@@ -597,18 +597,6 @@ describe Cask::Audit, :cask do
         it { is_expected.not_to fail_with(message) }
       end
 
-      context "when the download uses GitHub releases and has an appcast" do
-        let(:cask_token) { "github-with-appcast" }
-
-        it { is_expected.not_to fail_with(message) }
-      end
-
-      context "when the download uses GitHub releases and does not have an appcast" do
-        let(:cask_token) { "github-without-appcast" }
-
-        it { is_expected.to fail_with(message) }
-      end
-
       context "when the download is hosted on SourceForge and has an appcast" do
         let(:cask_token) { "sourceforge-with-appcast" }
 

Library/Homebrew/test/support/fixtures/cask/Casks/github-with-appcast.rb

-cask "github-with-appcast" do
-  version "1.0"
-  sha256 "a69e7357bea014f4c14ac9699274f559086844ffa46563c4619bf1addfd72ad9"
-
-  url "https://github.com/user/project/releases/download/#{version}/github.pkg"
-  appcast "https://github.com/user/project/releases.atom"
-  name "github"
-  homepage "https://github.com/user/project"
-
-  pkg "github.pkg"
-
-  uninstall pkgutil: "com.github"
-end

Library/Homebrew/test/support/fixtures/cask/Casks/github-without-appcast.rb

-cask "github-without-appcast" do
-  version "1.0"
-  sha256 "a69e7357bea014f4c14ac9699274f559086844ffa46563c4619bf1addfd72ad9"
-
-  url "https://github.com/user/project/releases/download/#{version}/github.pkg"
-  name "github"
-  homepage "https://github.com/user/project"
-
-  pkg "github.pkg"
-
-  uninstall pkgutil: "com.github"
-end