[Feature Request] Allow using local RSS file

[TheGroundZero]

I´d like to use this action as part of publishing my static website.
This website is first build in Hugo, then pushed to GitHub pages.
So there's a delay between building the site and the update being available online.
However, the RSS file is creating during the build stage.

As such, it would be nice to do e.g.

name: Deploy page

on:
  push:

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - name: Deploy page
        uses: my-repo/page-deployer

  publish:
    runs-on: ubuntu-latest
    needs: [deploy]
    steps:
      - name: Fetch RSS Data
        id: rss
        uses: CodingBull-dev/newest-rss-post-action@main
        with:
          rss: ./public/blog/rss.xml  # <---- use local file instead of remote

If this is already supported, could the documentation be updated to reflect this and to indicate what the path format should be?