Use exit code of tslint subprocess as exit code of react-scripts lint

Author: sverhoeven

packages/react-scripts/scripts/lint.js

@@ -11,5 +11,8 @@ var args = [
 var proc = spawn('tslint', args, {
     stdio: 'inherit'
 });
+proc.on('exit', (code) => {
+    process.exit(code);
+});
 
 // TODO also run eslint