remove mac from ci

since I do not have arm mac env and I can not prepare libwebrtc on that
environment.

Signed-off-by: Yuji Ito <llamerada.jp@gmail.com>

.github/workflows/ci.yaml

@@ -11,7 +11,8 @@ jobs:
     timeout-minutes: 60
     strategy:
       matrix:
-        os: [ubuntu-22.04, macos-latest]
+        # removing macos-latest since libwebrtc is not available on macos
+        os: [ubuntu-22.04]
     steps:
     - uses: actions/checkout@v2
     - uses: actions/setup-go@v5