[FIX] fix back check

src/App.vue

@@ -1,6 +1,6 @@
 <template lang="pug">
     .pos
-        form-wizard(title='' subtitle='' finishButtonText='Finalizar' :hideButtons='processing' color='#7c7bad' nextButtonText='Continuar' backButtonText='Volver' :validateOnBack='true' @on-complete='createSale' ref='wizard')
+        form-wizard(title='' subtitle='' finishButtonText='Finalizar' :hideButtons='processing' color='#7c7bad' nextButtonText='Continuar' backButtonText='Volver' @on-complete='createSale' ref='wizard')
             tab-content(title="Qué productos necesita?" :beforeChange="checkCart")
                 product-step
             tab-content(title="Quién es el cliente?" :beforeChange="checkCustomer")