Parallel builds support

[mizzy]

Walter supports parallel execution by run_after, but I'd like to execute main builds in parallel.

How about this YAML format to support this feature ?

pipeline:
  - name: 
    type: command
    command: echo "hello, world"
  - name: command_stage_2
    type: command
    command: echo "hello, world, command_stage_2"
  - name: command_stage_3
    type: command
    command: echo "hello, world, command_stage_3"
  - name: parallel builds
    type: parallel
    builds:
      - name: parallel build 1
        type: command
        command: parallel_command_1
      - name: parallel build 2
        type: command
        command: parallel_command_2
      - name: parallel build 3
        type: command
        command: parallel_command_3

Please check it.

[mizzy]

Fixed by #108

[takahi-i]

Thank you as always @mizzy!

[mizzy]

You're welcome!