upgrade to linter-0.1.30 (#9297)

* upgrade to linter-0.1.30

* add prefer_is_empty lint
* add directives_ordering lint
* add no_adjacent_strings_in_list lint
* add no_duplicate_case_values lint
* add prefer_collection_literals lint
* add prefer_const_constructors lint
* add prefer_contains lint
* add prefer_initializing_formals lint
* add unnecessary_null_aware_assignments lint
* add unnecessary_null_in_if_null_operators lint

packages/flutter_tools/lib/src/ios/mac.dart

diff --git a/packages/flutter_tools/lib/src/ios/mac.dart b/packages/flutter_tools/lib/src/ios/mac.dart
index 3c31e07..545fc3b 100644
--- a/packages/flutter_tools/lib/src/ios/mac.dart
+++ b/packages/flutter_tools/lib/src/ios/mac.dart
@@ -8,11 +8,11 @@
 import 'package:meta/meta.dart';
 
 import '../application_package.dart';
-import '../base/context.dart';
 import '../base/common.dart';
+import '../base/context.dart';
 import '../base/file_system.dart';
-import '../base/logger.dart';
 import '../base/io.dart';
+import '../base/logger.dart';
 import '../base/platform.dart';
 import '../base/process.dart';
 import '../base/process_manager.dart';