chore: Update create-jira-issue.yml

Author: doyeonk429

.github/workflows/create-jira-issue.yml

@@ -148,3 +148,10 @@ jobs:
           issue-number: ${{ github.event.issue.number }}
           body: '🔀 Branch Created: `${{ steps.branch.outputs.branch }}`'
 
+      - name: Assign issue author
+        uses: actions-cool/issues-helper@v3
+        with:
+          actions: 'add-assignees'
+          token: ${{ secrets.GITHUB_TOKEN }}
+          issue-number: ${{ github.event.issue.number }}
+          assignees: ${{ github.event.issue.user.login }}