Update WebRTC code version (2026-09-13T04:10:34).

Bug: None
Change-Id: I9d4a0d977c429a0ab193d66fb2807fd1fec3d61f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/502740
Bot-Commit: webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com <webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com>
Commit-Queue: webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com <webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#48580}

call/version.cc

diff --git a/call/version.cc b/call/version.cc
index a0e3c5e..b8c38aa 100644
--- a/call/version.cc
+++ b/call/version.cc
@@ -13,7 +13,7 @@
 namespace webrtc {
 
 // The timestamp is always in UTC.
-const char* const kSourceTimestamp = "WebRTC source stamp 2026-09-12T04:07:37";
+const char* const kSourceTimestamp = "WebRTC source stamp 2026-09-13T04:10:34";
 
 void LoadWebRTCVersionInRegister() {
   // Using volatile to instruct the compiler to not optimize `p` away even