matrix support list

[willzhang]

this work

kind: pipeline
spec:
  stages:
  - type: ci
    spec:
      steps:
      - name: test
        type: script
        strategy:
          type: matrix
          spec:
            axis:
              node_version: [ "12", "14" ]
        spec:
          image: node:${{ matrix.node_version }}
          run: |-
            npm install
            npm test

but this not work, i have a long list , so i hope list them as a list wilth - 12 -14

kind: pipeline
spec:
  stages:
  - type: ci
    spec:
      steps:
      - name: test
        type: script
        strategy:
          type: matrix
          spec:
            axis:
              node_version: 
                - 12
                - 14
        spec:
          image: node:${{ matrix.node_version }}
          run: |-
            npm install
            npm test

[willzhang]

alreayd support.