feat: tag the original author in the PR itself

Author: x0rw

.github/workflows/auto-pr-on-issue.yml

@@ -46,4 +46,7 @@ jobs:
           title: "[auto-pr] #${{ github.event.issue.number }}: ${{ github.event.issue.title }}"
           body: |
             This PR was automatically generated from issue #${{ github.event.issue.number }}.
+
+            **Authored by:** @${{ github.event.issue.user.login }}
+
             Closes #${{ github.event.issue.number }}.