Columns could use some adjustment

[BoSorensen]

After some use of the extension we have found that the width allocated for the Author is rarely sufficient. On the other hand, the width for Repository name is too much and probably the width for Reviewers is too much as well.

I would suggest a new distribution like this:
Author: Before 25% of available space -> Now 35%-ish of available space.
Repository: Before 25% of available space -> Now 15-20% of available space.
Reviewers: Before 33% of available space -> Now 25% of available space.

I'd be happy to provide a PR for this suggestion, if you think it's a good idea.