3.1.0

• Add init(webView:returnURLScheme:prefersEphemeralWebBrowserSession:) for the Venmo app switch flow. When a returnURLScheme is provided and the Venmo app is installed, PopupBridge sends that scheme to the web SDK as the return URL prefix (window.popupBridge.getReturnUrlPrefix()) so the Venmo app can deep-link back into your app.