Hashie feature to allow immutable properties

[hlascelles]

Would the Hashie community be open to a feature that would mark a Hashie::Dash property (say) as immutable?

eg

  class Person < Hashie::Dash
    include Hashie::Extensions::Immutable
  
    property :favourite_colour, immutable: false
    property :birthday, immutable: true
  end

[hlascelles]

And in just a few short minutes a change in our design has meant we can now work with fully frozen hashes. Nothing to see here.

[dblock]

If you think something here is valuable to hashie, PR please!