use recent version of args, eliminate deprecated usage
diff --git a/bin/extract_to_arb.dart b/bin/extract_to_arb.dart
index 181d4f1..a79023b 100644
--- a/bin/extract_to_arb.dart
+++ b/bin/extract_to_arb.dart
@@ -42,7 +42,7 @@
   if (args.length == 0) {
     print('Accepts Dart files and produces intl_messages.json');
     print('Usage: extract_to_arb [options] [files.dart]');
-    print(parser.getUsage());
+    print(parser.usage);
     exit(0);
   }
   var allMessages = {};
diff --git a/bin/generate_from_arb.dart b/bin/generate_from_arb.dart
index 9e7b1a7..5abf723 100644
--- a/bin/generate_from_arb.dart
+++ b/bin/generate_from_arb.dart
@@ -57,7 +57,7 @@
     print('Usage: generate_from_arb [options]'
         ' file1.dart file2.dart ...'
         ' translation1_<languageTag>.arb translation2.arb ...');
-    print(parser.getUsage());
+    print(parser.usage);
     exit(0);
   }
 
diff --git a/pubspec.yaml b/pubspec.yaml
index e72edcc..abef0f8 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -8,7 +8,7 @@
 documentation: http://www.dartdocs.org/documentation/intl/latest
 dependencies:
   analyzer: '>=0.13.2 <0.26.0'
-  args: '>=0.12.0 <0.14.0'
+  args: '>=0.12.1 <0.14.0'
   path: '>=0.9.0 <2.0.0'
   petitparser: '>=1.1.3 <2.0.0'
 dev_dependencies: