Update URI of TransportSequenceNumberV2

The previous URI was a placeholder and is not valid. The URI
https://webrtc.org/experiments/rtp-hdrext/transport-wide-cc-02/
must be used instead.

Bug: webrtc:10264
Change-Id: Ibabde599b5bbd116c1c5e86ba0c9c64019bf7026
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/126360
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Commit-Queue: Johannes Kron <kron@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27051}
diff --git a/modules/rtp_rtcp/source/rtp_header_extensions.h b/modules/rtp_rtcp/source/rtp_header_extensions.h
index e36c83f..8aacb9a 100644
--- a/modules/rtp_rtcp/source/rtp_header_extensions.h
+++ b/modules/rtp_rtcp/source/rtp_header_extensions.h
@@ -97,8 +97,7 @@
   static constexpr uint8_t kValueSizeBytes = 4;
   static constexpr uint8_t kValueSizeBytesWithoutFeedbackRequest = 2;
   static constexpr const char kUri[] =
-      "http://www.ietf.org/id/"
-      "draft-holmer-rmcat-transport-wide-cc-extensions-02";
+      "http://www.webrtc.org/experiments/rtp-hdrext/transport-wide-cc-02";
   static bool Parse(rtc::ArrayView<const uint8_t> data,
                     uint16_t* transport_sequence_number,
                     absl::optional<FeedbackRequest>* feedback_request);