Unable to send LINE message

`linebot: APIError 400 The property, 'to', in the request body is invalid (line: -, column: -)`

Here is my YML:

```
on:
rss:
url: https://hnrss.org/newest?points=300&count=3
jobs:
build:
name: send rss message
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@master
- name: send custom message with args
uses: appleboy/line-action@master
with:
secret: ${{ secrets.LINE_CHANNEL_SECRET }}
token: ${{ secrets.LINE_CHANNEL_TOKEN }}
group: ${{ secrets.LINE_GROUP_ID }}
message: line message from GitHub Actions - ${{on.rss.outputs.title}}
```

The report provides only the workflow YAML and the `appleboy/line-action@master` entry point; start by reproducing it with the referenced LINE secrets and group value. Trace how the workflow supplies the `to` value to the LINE request, then confirm a corrected workflow sends the RSS message.

Written by the indexing model from the issue text.