Allow accessing version in livecheck blocks.

Library/Homebrew/livecheck.rb

@@ -8,6 +8,8 @@
 # This information is used by the `brew livecheck` command to control its
 # behavior.
 class Livecheck
+  extend Forwardable
+
   # A very brief description of why the formula/cask is skipped (e.g. `No longer
   # developed or maintained`).
   # @return [String, nil]
@@ -107,6 +109,9 @@ class Livecheck
     end
   end
 
+  delegate version: :@formula_or_cask
+  private :version
+
   # Returns a `Hash` of all instance variable values.
   # @return [Hash]
   def to_hash