Why is the official github no longer updated last year? How do I build the latest image?
EOSIO is now Antelope (see Antelope.io) and further developed by the EOS Network Foundation. In addition a Coallition of multiple Antelope-based chains has been formed.
You can find the latest developments and maintained Repositories in github.com/antelopeio, the "leap"-repository is what previously was the eosio-repository, containing code and build instructions for programs like nodeos, cleos, keosd etc.