Update Fuchsia API version

Bug: b/291545987
Change-Id: I7b5413ee388df9e2fd2e4c15c9700478b5d2c388
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/312180
Auto-Submit: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#40443}

.gn

diff --git a/.gn b/.gn
index ed92a1b..02cfb6d 100644
--- a/.gn
+++ b/.gn
@@ -74,7 +74,7 @@
   # Chromium fix resolves the problem.
   fuchsia_sdk_readelf_exec =
       "//third_party/llvm-build/Release+Asserts/bin/llvm-readelf"
-  fuchsia_target_api_level = 9
+  fuchsia_target_api_level = 11
 
   use_cxx17 = true
 }