[animations] fix dates in changelog (flutter#102)

Author: goderbauer

packages/animations/CHANGELOG.md

@@ -1,18 +1,18 @@
-## [1.0.0+3] - February 18, 20200
+## [1.0.0+3] - February 18, 2020
 
 * Update README.md to better describe Material motion
 
 
-## [1.0.0+2] - February 18, 20200
+## [1.0.0+2] - February 18, 2020
 
 * Fixes to pubspec.yaml
 
 
-## [1.0.0+1] - February 18, 20200
+## [1.0.0+1] - February 18, 2020
 
 * Fixes to pubspec.yaml
 
 
-## [1.0.0] - February 18, 20200
+## [1.0.0] - February 18, 2020
 
 * Initial release