[pigeon] fixed style issue with implied return null (#544)

diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index 2620359..7c89793 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.13
+
+* [style] Fixes new style rules for Dart analyzer.
+
 ## 1.0.12
 
 * [java] Fixes enum support for null values.
diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
index 86ef5b3..de2bb02 100644
--- a/packages/pigeon/lib/generator_tools.dart
+++ b/packages/pigeon/lib/generator_tools.dart
@@ -8,7 +8,7 @@
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '1.0.12';
+const String pigeonVersion = '1.0.13';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
diff --git a/packages/pigeon/lib/pigeon_lib.dart b/packages/pigeon/lib/pigeon_lib.dart
index e5b7814..dcdb578 100644
--- a/packages/pigeon/lib/pigeon_lib.dart
+++ b/packages/pigeon/lib/pigeon_lib.dart
@@ -630,6 +630,7 @@
         lineNumber: _calculateLineNumber(source, node.offset),
       ));
     }
+    return null;
   }
 
   @override
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index c09f93e..8e5b454 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/master/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3Apigeon
-version: 1.0.12 # This must match the version in lib/generator_tools.dart
+version: 1.0.13 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: '>=2.12.0 <3.0.0'