Bump the version to 1.4.1. (#21)

diff --git a/pubspec.yaml b/pubspec.yaml
index 87980ea..48e799b 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: path
-version: 1.4.0
+version: 1.4.1
 author: Dart Team <misc@dartlang.org>
 description: >
  A string-based path manipulation library. All of the path operations you know