Prepare to publish (dart-lang/stream_transform#126)

pkgs/stream_transform/CHANGELOG.md

diff --git a/pkgs/stream_transform/CHANGELOG.md b/pkgs/stream_transform/CHANGELOG.md
index 2bae497..7b68aa5 100644
--- a/pkgs/stream_transform/CHANGELOG.md
+++ b/pkgs/stream_transform/CHANGELOG.md
@@ -1,4 +1,4 @@
-## 2.0.0-nullsafety.0-dev
+## 2.0.0-nullsafety.0
 
 - Migrate to null safety.
 - Improve tests of `switchMap` and improve documentation with links and

pkgs/stream_transform/pubspec.yaml

diff --git a/pkgs/stream_transform/pubspec.yaml b/pkgs/stream_transform/pubspec.yaml
index ba4bd51..4e5b379 100644
--- a/pkgs/stream_transform/pubspec.yaml
+++ b/pkgs/stream_transform/pubspec.yaml
@@ -1,7 +1,7 @@
 name: stream_transform
 description: A collection of utilities to transform and manipulate streams.
 homepage: https://github.com/dart-lang/stream_transform
-version: 2.0.0-nullsafety.0-dev
+version: 2.0.0-nullsafety.0
 
 environment:
   sdk: ">=2.12.0-0 <3.0.0"