Add BranchName and ReleaseBranches protos

BUG=b:177487002, chromium:1157948
TEST=generate.sh

Change-Id: I564e62101d6edff9285e939b42d2b0a150c4e29e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2648220
Commit-Queue: Jack Neus <jackneus@google.com>
Commit-Queue: George Engelbrecht <engeg@google.com>
Reviewed-by: George Engelbrecht <engeg@google.com>
Auto-Submit: Jack Neus <jackneus@google.com>
2 files changed