Add matrix input

[sue445]

Motivation

I often use matrix job.

I want to know from Slack notifications which matrix and which parameter of the test succeeded (or failed).

So I implemented an easy way to display this information.

Example

jobs:
  matrix:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        name1:
          - value1a
          - value1b
        name2:
          - value2a
          - value2b

    steps:
      - name: Slack Notification
        uses: act10ns/slack@v2
        if: always()
        with:
          status: ${{ job.status }}
          webhook-url: ${{ secrets.SLACK_WEBHOOK }}
          matrix: ${{ toJson(matrix) }}

[satterly]

This is awesome. Thanks a lot. 👍