[infra] More work on chrome_release_branch

- Actually create the new branch
- Create the CL to update the Chrome milestone

Bug: skia:8932
Change-Id: If49a5b8893b90d0285b3b576c5af94e42d40f803
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/208671
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Ben Wagner aka dogben <benjaminwagner@google.com>
Reviewed-by: Heather Miller <hcm@google.com>
2 files changed