Change english validation error messages

src/i18n/en.json

@@ -74,11 +74,11 @@
     "registration": "Registration",
     "token": "Invite token",
     "validations": {
-      "username_required": "should not be blank",
-      "fullname_required": "should not be blank",
-      "email_required": "should not be blank",
-      "password_required": "should not be blank",
-      "password_confirmation_required": "should not be blank",
+      "username_required": "cannot be left blank",
+      "fullname_required": "cannot be left blank",
+      "email_required": "cannot be left blank",
+      "password_required": "cannot be left blank",
+      "password_confirmation_required": "cannot be left blank",
       "password_confirmation_match": "should be the same as password"
     }
   },