Prepare to publish stable null safety (#46)

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9aed3a0..3bc5b71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.3.0
+
+* Stable release for null safety.
+
 ## 1.3.0-nullsafety.5
 
 * Update SDK constraints to `>=2.12.0-0 <3.0.0` based on beta release

pubspec.yaml

diff --git a/pubspec.yaml b/pubspec.yaml
index 2e8a0fb..0501c93 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: typed_data
-version: 1.3.0-nullsafety.5
+version: 1.3.0
 
 description: >-
   Utility functions and classes related to the dart:typed_data library.
@@ -9,7 +9,7 @@
   sdk: ">=2.12.0-0 <3.0.0"
 
 dependencies:
-  collection: '>=1.15.0-nullsafety <1.15.0'
+  collection: ^1.15.0
 
 dev_dependencies:
   pedantic: ^1.10.0-nullsafety