[instrumentation_adapter] update for release (flutter#2051)

Author: collinjackson

packages/instrumentation_adapter/pubspec.yaml

@@ -1,6 +1,6 @@
 name: instrumentation_adapter
 description: Runs tests that use the flutter_test API as platform native instrumentation tests.
-version: 0.1.1
+version: 0.1.2
 author: Flutter Team <[email protected]>
 homepage: https://github.com/flutter/plugins/tree/master/packages/instrumentation_adapter