message: doc: vm is no longer a submodule
diff: @@ -85,10 +85,6 @@ brew install autoconf libtool
  git clone https://github.com/nervosnetwork/ckb.git
  cd ckb
  -# get ckb-vm submodule
  -git submodule init
  -git submodule update
  -
  # build in release mode
  cargo build --release
  ```
  