AS_TOOK and AS_JOB return undefined/not found when running via matrix

[nautilytics]

Describe the bug

Similar to #135, I am trying to send a Slack message and am including process.env.AS_TOOK in the custom_payload. In the below example, in Slack, I am seeing that not only is the AS_TOOK variable not found, but also AS_JOB is not found.

I followed the instructions to set things up for MATRIX_CONTEXT: ${{ toJson(matrix) }}, but I'm not sure it is working properly.

To Reproduce

name: E2E Tests and Checks

on:
  push:

jobs:
  build:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        node: [ 14.15.5 ]

    name: E2E on Node v${{ matrix.node }}
    steps:
      - name: Send message to Slack
        uses: 8398a7/action-slack@v3.9.0
        with:
          icon_emoji: ':react:'
          status: custom
          fields: workflow,job,commit,repo,ref,author,took
          custom_payload: |
            {
              attachments: [{
                color: '${{ job.status }}' === 'success' ? 'good' : '${{ job.status }}' === 'failure' ? 'danger' : 'warning',
                text: `${process.env.AS_WORKFLOW}\n${process.env.AS_JOB} (${process.env.AS_COMMIT}) of ${process.env.AS_REPO}@${process.env.AS_REF} by ${process.env.AS_AUTHOR} ${{ job.status }} in ${process.env.AS_TOOK}`,
              }]
            }
        env:
          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
          MATRIX_CONTEXT: ${{ toJson(matrix) }}
        if: always()

Output in Slack

E2E Tests and Checks
Job is not found.
Check the matrix or job name. 
(438f0ad4) of <repo>@refs/heads/<branch>/gh-action-slack-notification 
by Chris<email_address> success in undefined

Expected behavior

I expected the job to be found and outputted in the custom_payload and the amount of time taken to be n seconds.

[8398a7]

If name is changed when using matrix, it will not work.
This specification will be described in the documentation.

I have also created an issue for it to work.
If there is further discussion, please do so here.
refs: #150