Tighten the constraint on args.

Closes #396

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1684063004 .
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b90df3..ed15d9f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 0.12.10+2
+
+* Re-add help output separators.
+
+* Tighten the constraint on `args`.
+
 ## 0.12.10+1
 
 * Temporarily remove separators from the help output. Version 0.12.8 was
diff --git a/lib/src/runner/configuration/args.dart b/lib/src/runner/configuration/args.dart
index 9f66146..47df545 100644
--- a/lib/src/runner/configuration/args.dart
+++ b/lib/src/runner/configuration/args.dart
@@ -30,6 +30,7 @@
   // We pass null values rather than defaults to [new Configuration] so that it
   // merges properly with the config file.
 
+  parser.addSeparator("======== Selecting Tests");
   parser.addOption("name",
       abbr: 'n',
       help: 'A substring of the name of the test to run.\n'
@@ -50,6 +51,7 @@
       allowMultiple: true);
   parser.addOption("exclude-tag", hide: true, allowMultiple: true);
 
+  parser.addSeparator("======== Running Tests");
   parser.addOption("platform",
       abbr: 'p',
       help: 'The platform(s) on which to run the tests.',
@@ -73,6 +75,7 @@
           'Currently only supported for browser tests.',
       negatable: false);
 
+  parser.addSeparator("======== Output");
   parser.addOption("reporter",
       abbr: 'r',
       help: 'The runner used to print test results.',
diff --git a/pubspec.yaml b/pubspec.yaml
index 9e90a85..b4ccf2c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: test
-version: 0.12.10+1
+version: 0.12.10+2
 author: Dart Team <misc@dartlang.org>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/test
@@ -7,7 +7,7 @@
   sdk: '>=1.13.0 <1.16.0'
 dependencies:
   analyzer: '>=0.23.0 <0.28.0'
-  args: '>=0.12.1 <0.14.0'
+  args: '^0.13.1'
   async: '^1.6.0'
   barback: '>=0.14.0 <0.16.0'
   collection: '^1.1.0'