message: Update Homebrew formula to v0.4.0
diff: class Rage < Formula
  desc "[BETA] A simple, secure, and modern encryption tool."
  homepage "https://str4d.xyz/rage"
  - url "https://github.com/str4d/rage/archive/v0.3.1.tar.gz"
  - sha256 "6eb17ac91bd134a8abef16b30953820c5dc8bd90273e0a2c8daefbfcdc6245e1"
  - version "0.3.1"
  + url "https://github.com/str4d/rage/archive/v0.4.0.tar.gz"
  + sha256 "612754f0a78517dd3ac490a9860b996317dbabcc745e307b9c6e6cab4379c1e7"
  + version "0.4.0"
  depends_on "rust" => :build
  