[package_info_plus] Set dummy version for the example

Author: jpnurmi

packages/package_info_plus/example/pubspec.yaml

@@ -1,5 +1,7 @@
 name: package_info_example
 description: Demonstrates how to use the package_info_plus plugin.
+version: 1.2.3+4
+publish_to: 'none'
 
 environment:
   sdk: ">=2.7.0 <3.0.0"