Provide a summary of the updates

[ccremer]

At the end of a run, the output might be cluttered with Diffs and Logs.
The repo update should provide a summary table.

This table could look like this:

Repo	Status	Changed files	Pull request
repo-1	Success	README.adoc, .gitignore and 12 others	https://github.com/.../12
repo-2	Failure	unknown	not found