The pull to refresh feature is part of Pega 8.2 which will be released soon. There'll be no update for 7.3 but you can consider implementing custom js code to detect swipe down gesture and trigger page reload.
I have tried to get the functionality by writing custom JS, it is working, but the issue is that, when i pull down to refresh it is not updating the data, when the data is inserted from soap UI. I have written the code in a section named as "PullRefresh" and embedded the section in another section named as "OrderList". Attached is the HTML file, please have a look and guide me what i have missed.