Add example, prepare for 1.4.3 ship
diff --git a/example/example.dart b/example/example.dart
new file mode 100644
index 0000000..890343c
--- /dev/null
+++ b/example/example.dart
@@ -0,0 +1,17 @@
+// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:pub_semver/pub_semver.dart';
+
+void main() {
+  final range = VersionConstraint.parse('^2.0.0');
+
+  for (var version in [
+    Version.parse('1.2.3-pre'),
+    Version.parse('2.0.0+123'),
+    Version.parse('3.0.0-dev'),
+  ]) {
+    print('$version ${version.isPreRelease} ${range.allows(version)}');
+  }
+}
diff --git a/pubspec.yaml b/pubspec.yaml
index 1297883..e2ac3b0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: pub_semver
-version: 1.4.3-dev
+version: 1.4.3
 
 description: >-
  Versions and version constraints implementing pub's versioning policy. This