Update WebRTC code version (2026-07-18T04:04:01).

Bug: None
Change-Id: I7421b2dad965a07ed9f15ccb3fa85f140b970f3a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/489880
Commit-Queue: webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com <webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com>
Bot-Commit: webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com <webrtc-version-updater@webrtc-ci.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#48202}

call/version.cc

diff --git a/call/version.cc b/call/version.cc
index 242a7ae..d2c12fd 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 2026-07-17T04:04:31";
+const char* const kSourceTimestamp = "WebRTC source stamp 2026-07-18T04:04:01";
 
 void LoadWebRTCVersionInRegister() {
   // Using volatile to instruct the compiler to not optimize `p` away even