Merge pull request #125 from tauu/export-terminal-target-platform

fix: export TerminalTargetPlatform

lib/core.dart

@@ -14,3 +14,4 @@ export 'src/core/input/keys.dart';
 export 'src/core/mouse.dart';
 export 'src/core/state.dart';
 export 'src/terminal.dart';
+export 'src/utils/platform.dart';