* create and publish github release
* creates a tarball of 'lotus', 'lotus-storage-miner' and
'lotus-seal-worker' for darwin and linux
* computes and saves IPFS CID and sha512sum for each architecture
* creates a github release and uploads all artifacts
* triggered by tags matching regex /^v\d+\.\d+\.\d+$/ ie. v0.1.0
* add licenses and readme
