roll_util: Add link to repository being rolled

Add links to the repositories being rolled in the commit message. This
makes it easier to track down the commits themselves.

Change-Id: I848a411cc911e8c539d75e767061707ed79c0097
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/56321
Reviewed-by: Keir Mierle <keir@google.com>
Commit-Queue: Rob Mohr <mohrr@google.com>
37 files changed