Add the URL attribute to cricket::Candiate. (Objc wrapper)

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCIceCandidate.h

Index: webrtc/sdk/objc/Framework/Headers/WebRTC/RTCIceCandidate.h
diff --git a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCIceCandidate.h b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCIceCandidate.h
index 9f472b8df057a432b389c1122a1368524c8200c1..3b7f3e26e5ac136c0da5781deb781fced53410c3 100644
--- a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCIceCandidate.h
+++ b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCIceCandidate.h
@@ -32,6 +32,9 @@ RTC_EXPORT
 /** The SDP string for this candidate. */
 @property(nonatomic, readonly) NSString *sdp;
 
+/** The URL of the ICE server which this candidate is gathered from. */
+@property(nonatomic, readonly, nullable) NSString *serverUrl;
+
 - (instancetype)init NS_UNAVAILABLE;
 
 /**