ci: Try to fix "Cannot find module 'appdmg'"

.github/workflows/main.yml

@@ -37,6 +37,9 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: 20
+      - name: Set up Python for appdmg to be installed
+        if: ${{ matrix.os.name == 'macos' }}
+        run: brew install python-setuptools
       - name: Install dependencies
         run: npm ci
       - name: Update build info