[animations] Bump version for NNBD stable (#293)

diff --git a/packages/animations/pubspec.yaml b/packages/animations/pubspec.yaml
index c6edcca..81150b1 100644
--- a/packages/animations/pubspec.yaml
+++ b/packages/animations/pubspec.yaml
@@ -1,10 +1,10 @@
 name: animations
 description: Fancy pre-built animations that can easily be integrated into any Flutter application.
-version: 2.0.0-nullsafety.1
+version: 2.0.0
 homepage: https://github.com/flutter/packages/tree/master/packages/animations
 
 environment:
-  sdk: '>=2.12.0-0 <3.0.0'
+  sdk: '>=2.12.0-259.9.beta <3.0.0'
 
 dependencies:
   flutter:
@@ -13,4 +13,4 @@
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  vector_math: ">=2.1.0-nullsafety.5 <3.0.0"
+  vector_math: ^2.1.0