Use head blocks instead of devel blocks

Because devel blocks has been deprecated since Homebrew 2.4.0.
Please see Homebrew/brew#7688 for details.

Fix #2

aglio.rb

@@ -1,18 +1,18 @@
-require "language/node"
-
 class Aglio < Formula
+  require "language/node"
+
   desc "API Blueprint renderer"
   homepage "https://github.com/danielgtaylor/aglio/"
+  license "MIT"
 
-  depends_on "node"
-
-  devel do
+  head do
     url "https://github.com/Gasol/aglio/archive/333da5.tar.gz"
     version "333da5"
     sha256 "7952eccf8ee89a2a05e6a89160d855f377777132a5637782db369b84e4a35d64"
-
   end
 
+  depends_on "node"
+
   def install
     system "npm", "install", *Language::Node.local_npm_install_args
     system "npm", "run-script", "prepare"