message: chore: CHANGELOG for v0.12.2
diff: All notable changes to this project will be documented in this file.
  See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
  +# [v0.12.2](https://github.com/nervosnetwork/ckb/compare/v0.12.1...v0.12.2) (2019-05-20)
  +
  +### Features
  +
  +* #838: Limit name in chainspec (@doitian)
  +
  + Only `ckb_dev` is allowed in the chainspec loaded from file.
  +
  +* #840: Modify subcommand `ckb init`. (@doitian)
  +
  + - Export `specs/dev.toml` when init for dev chain.
  + - Deprecate option `--export-specs`.
  + - Rename `spec` to `chain` in options.
  + - Add option `--chain` and deprecate `--spec`
  + - Add option `--list-chains` and deprecate `--list-specs`
  + - Rename `export` to `create` in messages.
  +
  +* #843: Secp256k1 block assembler (@doitian)
  +
  + - Remove the default block assembler config. If user want to mine, they must configure it.
  +
  +* #856: Revamp the secp256k1 support in CKB (@doitian)
  +
  + - Remove keygen feature added in #843
  + - Add `ckb cli blake160` and `ckb cli blake256` utilities to compute hash.
  + - Add `ckb cli secp256k1-lock` to print block assembler config from
  + a secp256k1 pubkey.
  +
  +
  # [v0.12.1](https://github.com/nervosnetwork/ckb/compare/v0.12.0...v0.12.1) (2019-05-18)
  ### Bug Fixes
  