Fix iOS version for internal.client.webrtc perf test

This adjusts iOS version to the actual one on the tester bot.

Bug: webrtc:10047
Change-Id: I7d104f331450192142c8c2c1259a3207dcee45ed
Reviewed-on: https://webrtc-review.googlesource.com/c/113420
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Artem Titarenko <artit@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25917}

tools_webrtc/ios/internal.client.webrtc/iOS64_Perf.json

diff --git a/tools_webrtc/ios/internal.client.webrtc/iOS64_Perf.json b/tools_webrtc/ios/internal.client.webrtc/iOS64_Perf.json
index c71c0a8..f134511 100644
--- a/tools_webrtc/ios/internal.client.webrtc/iOS64_Perf.json
+++ b/tools_webrtc/ios/internal.client.webrtc/iOS64_Perf.json
@@ -22,7 +22,7 @@
     {
       "include": "perf_tests.json",
       "device type": "iPhone 7",
-      "os": "11.4.1"
+      "os": "11.0.3"
     }
   ]
 }