Issue template front matter env var usage for assignees name doesn't work

[seanparkross]

Hi there 👋 Thanks for the code.

Using an env var in the assignees field in the front matter of an issue template markdown doesn't work.

Is there a way to fix this:

Workflow:

      - name: Create issue if patch failed
        if:
          some... logic...
        uses: JasonEtco/create-an-issue@v2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          PR_URL: ${{ github.event.pull_request.html_url }}
          PR_AUTHOR: ${{ github.event.pull_request.user.login }}
        with:
          filename: .github/ISSUE_TEMPLATE/sync-failed.md

Issue template:

---
title: Sync Failed for PR {{ env.PR_NUMBER }}
labels: sync-failed
assignees: {{ env.PR_AUTHOR }}
---

## Sync Failed

The GitHub Action failed to do its thing from PR #{{ env.PR_NUMBER }} and @{{ env.PR_AUTHOR}} to the blah blah blah...

Error:

Run JasonEtco/create-an-issue@v2
⬤  debug     Reading from file .github/ISSUE_TEMPLATE/sync-failed.md
✖  error     An error occurred while parsing the issue. This might be caused by a malformed issue title, or a typo in the labels or assignees. Check .github/ISSUE_TEMPLATE/sync-failed.md!
✖  error     {
  _errors: [],
  assignees: {
    _errors: [
      'Expected array, received object',
      'Expected string, received object'
    ]
  }
}
Error: An error occurred while parsing the issue. This might be caused by a malformed issue title, or a typo in the labels or assignees. Check .github/ISSUE_TEMPLATE/sync-failed.md!

undefined

Removing the assignees front matter item fixes it. But I'd really like that dynamic assignment. Any fix?