Use ponyc release version when building arm64 macos nightlies

It was supposed to have been switched ages ago but wasn't.

.github/workflows/nightlies.yml

@@ -92,7 +92,7 @@ jobs:
     steps:
       - uses: actions/[email protected]
       - name: install ponyc
-        run: bash .ci-scripts/macos-arm64-install-pony-tools.bash nightly
+        run: bash .ci-scripts/macos-arm64-install-pony-tools.bash release
       - name: brew install dependencies
         run: brew install coreutils
       - name: pip install dependencies