Change ndk version for mac

.github/workflows/test-android-mac.yml

@@ -23,7 +23,7 @@ jobs:
       uses: reactivecircus/android-emulator-runner@v2
       with:
         api-level: 29
-        ndk: 21.0.6528147
+        ndk: 21.0.6472646
         cmake: 3.10.2.4988404
         working-directory: ./lib/android_build
         script: ./testandlog