Add context output after run

[Théo]

For link other actions, it would be useful to have a output to know if is a new version and if the new tag is created.

eg:

• changed : either "true" or "false", indicates whether the version has changed.
• Can access the value like this : steps.ID.outputs.changed.

Know it's possible with process.stdout.write(`::set-output name=changed::${ some_value }\` + os.EOL).

[Pascal]

Agree! Do you like to create a PR for this?