Change version to 2.0.0-nullsafety.0 for consistency.
diff --git a/pubspec.yaml b/pubspec.yaml
index 48b8d3c..c1cfd94 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: package_config
-version: 2.0.0-dev
+version: 2.0.0-nullsafety.0
 description: Support for working with Package Configuration files.
 homepage: https://github.com/dart-lang/package_config