Update WebRTC code version (2026-09-12T04:07:37).

Bug: None
Change-Id: Ie506422091aed5ed6d12683034d65de6360a0152
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/502420
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@{#48578}

call/version.cc

diff --git a/call/version.cc b/call/version.cc
index 1dfc12b..a0e3c5e 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 2026-09-11T04:11:18";
+const char* const kSourceTimestamp = "WebRTC source stamp 2026-09-12T04:07:37";
 
 void LoadWebRTCVersionInRegister() {
   // Using volatile to instruct the compiler to not optimize `p` away even