adjust flatpickr to support nested forms

Author: jonasjabari

spec/dummy/app/matestack/dummy/components/form/flatpickr.rb

@@ -17,7 +17,7 @@ def vue_props
   def response
     # exactly one root element is required since this is a Vue.js component template
     div class: "form-flatpickr-component" do
-      label input_label, for: attribute_key,  class: "form-label" if input_label
+      label input_label, ":for": id,  class: "form-label" if input_label
       input input_attributes.merge(bootstrap_flatpickr_input_attributes)
       render_errors
       render_form_text