fix(validate): en-US translations

Author: Menno Luiten

packages/validate/translations/en-US.js

@@ -3,9 +3,11 @@ import en from './en.js';
 export default {
   ...en,
   error: {
+    ...en.error,
     isDate: 'Please enter a valid date (MM/DD/YYYY).',
   },
   warning: {
+    ...en.warning,
     isDate: 'Please enter a valid date (MM/DD/YYYY).',
   },
 };