chore: bump to `stark-backend` v1.2.1-rc.5#2158

jonathanpwang wants to merge 3 commits intomainopenvm-org/openvm:mainfrom

chore/stark-backend-1.2.0-rc.5openvm-org/openvm:chore/stark-backend-1.2.0-rc.5Copy head branch name to clipboard