ci : use macos-latest for arm64 webgpu build (#16029)

This commit updates the runs-on field for the macOS arm64 webgpu build
job to use macos-latest instead of just latest.

The motivation for this is that this job can wait for a runner to pick
up the job for a very long time, sometimes over 7 hours. This is an
attempt to see if this change can help reduce the wait time.

Refs: https://github.com/ggml-org/llama.cpp/actions/runs/17754163447/job/50454257570?pr=16004

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 7f2dccde0cb91ec93c1d4426e972df556ad3f1b9..0a00c85b7340bb4f180c7f4ea3cc6e657b551550 100644 (file)
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -138,7 +138,7 @@ jobs:
           ctest -L main --verbose --timeout 900
 
   macOS-latest-cmake-arm64-webgpu:
-    runs-on: latest
+    runs-on: macos-latest
 
     steps:
       - name: Clone