SkQP: update tools/skqp/gn_to_bp.py, add release script

No-Try: true
Change-Id: Id8cfba15d70700d4d38c7db81599f6d56fb93cdd
Reviewed-on: https://skia-review.googlesource.com/c/190306
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Derek Sollenberger <djsollen@google.com>
2 files changed