stable null safety release (#42)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ade9ff..3c942aa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.0.0
+
+* Stable null safety stable release.
+
 ## 4.0.0-nullsafety
 
 * Migrate to null safety.
diff --git a/pubspec.yaml b/pubspec.yaml
index 9592540..b2939aa 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: http_parser
-version: 4.0.0-nullsafety
+version: 4.0.0
 description: >-
   A platform-independent package for parsing and serializing HTTP formats.
 homepage: https://github.com/dart-lang/http_parser
@@ -8,18 +8,12 @@
   sdk: '>=2.12.0-0 <3.0.0'
 
 dependencies:
-  charcode: ^1.2.0-nullsafety
-  collection: ^1.15.0-nullsafety.2
-  source_span: ^1.8.0-nullsafety
-  string_scanner: ^1.1.0-nullsafety
-  typed_data: ^1.3.0-nullsafety.2
+  charcode: ^1.2.0
+  collection: ^1.15.0
+  source_span: ^1.8.0
+  string_scanner: ^1.1.0
+  typed_data: ^1.3.0
 
 dev_dependencies:
-  pedantic: ^1.10.0-nullsafety
+  pedantic: ^1.10.0
   test: ^1.16.0-nullsafety.4
-
-# Because these packages depend on the prev4 version of this package
-dependency_overrides:
-  shelf: 0.7.9
-  shelf_static: 0.2.8
-  test: 1.16.0-nullsafety.9