Remove `-dev` from version number.

pubspec.yaml

diff --git a/pubspec.yaml b/pubspec.yaml
index 2ec0d8e..242344c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,7 +2,7 @@
 description: >-
   Utilities for the Dart VM Runtime including support for ANSI colors,
   file copying, and standard exit code values.
-version: 0.3.5-dev
+version: 0.3.5
 homepage: https://github.com/dart-lang/io
 
 environment: