Bump to version 5.1.0

PiperOrigin-RevId: 427859393
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5537119..a70a770 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,4 @@
-## 5.1.0-dev
+## 5.1.0
 
 * In creating mocks for a pre-null-safe library, opt out of null safety in the
   generated code.
diff --git a/lib/src/version.dart b/lib/src/version.dart
index f63bc21..6347bc3 100644
--- a/lib/src/version.dart
+++ b/lib/src/version.dart
@@ -1 +1 @@
-const packageVersion = '5.1.0-dev';
+const packageVersion = '5.1.0';
diff --git a/pubspec.yaml b/pubspec.yaml
index 29ebe0c..c645183 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: mockito
-version: 5.1.0-dev
+version: 5.1.0
 
 description: >-
   A mock framework inspired by Mockito with APIs for Fakes, Mocks,