bump version for release (#37)

diff --git a/pubspec.yaml b/pubspec.yaml
index 6f20954..ee0a5f7 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: typed_data
-version: 1.3.0-nullsafety.1
+version: 1.3.0-nullsafety.2
 
 description: >-
   Utility functions and classes related to the dart:typed_data library.