main.star: update protobuf deps to v35.1

Change-Id: I017866e121b0d2c87918bc6228ce8272a6fe5ee5
Reviewed-on: https://go-review.googlesource.com/c/build/+/810800
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Stapelberg <stapelberg@google.com>
Auto-Submit: Nicolas Hillegeer <aktau@google.com>
Reviewed-by: Nicolas Hillegeer <aktau@google.com>