feat: add macos build support

cli/commands/build/macos.dart

@@ -0,0 +1,42 @@
+import 'dart:async';
+import 'dart:io';
+
+import 'package:args/command_runner.dart';
+import 'package:path/path.dart';
+
+import 'common.dart';
+
+class MacosBuildCommand extends Command with BuildCommandCommonSteps {
+  @override
+  String get description => "Macos Build command";
+
+  @override
+  String get name => "macos";
+
+  @override
+  FutureOr? run() async {
+    await bootstrap();
+
+    await shell.run(
+      """
+      flutter build macos
+      appdmg appdmg.json ${join(cwd.path, "build", "Spotube-macos-universal.dmg")}
+      flutter_distributor package --platform=macos --targets pkg --skip-clean
+      """,
+    );
+
+    final ogPkg = File(
+      join(
+        cwd.path,
+        "dist",
+        pubspec.version.toString(),
+        "spotube-${pubspec.version}-macos.pkg",
+      ),
+    );
+
+    await ogPkg.copy(
+      join(cwd.path, "build", "Spotube-macos-universal.pkg"),
+    );
+    await ogPkg.delete();
+  }
+}