2fa can't be activated on app.pullrequest.com

**Summary:** Hello Team, Since you are using deprecated google chart API service (which doesn't work now) for generating 2fa qr code image, users cannot setup 2fa for securing account. ### Steps To Reproduce 1. Log into https://app.pullrequest.com 2. Go to "User Settings" -> "Security" -> "Two-Factor Authentication" 3. You cannot when you try enabling it ## Impact I understand it is kinda technical bug. But I decided to report as it literally affects all existing and new users by not allowing them to secure their account.