Where does the action look for the `_config.yml` file?

[fragile-credences]

Sorry for basic question.

I'm using a <user>.github.io repo, with a very simple workflow:

name: Build and deploy Jekyll site to GitHub Pages

on:
  push:
    branches:
      - master

jobs:
  github-pages:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: helaili/jekyll-action@v2
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          target_branch: test-branch

The action seems to look for the _config.yml file in the wrong place, because it fails with

Configuration file: /github/workspace/./_config.yml
            Source: /github/workspace/.
       Destination: build
 Incremental build: disabled. Enable with --incremental
      Generating... 
             Error: could not read file /github/workspace/vendor/bundle/ruby/2.7.0/gems/jekyll-3.9.1/lib/site_template/_posts/0000-00-00-welcome-to-jekyll.markdown.erb: Invalid date '<%= Time.now.strftime('%Y-%m-%d %H:%M:%S %z') %>': Document 'vendor/bundle/ruby/2.7.0/gems/jekyll-3.9.1/lib/site_template/_posts/0000-00-00-welcome-to-jekyll.markdown.erb' does not have a valid date in the YAML front matter.
             ERROR: YOUR SITE COULD NOT BE BUILT:

My website and its _config.yml are on the root of the repo. I have tried various plausible values for jekyll_src without success.

[helaili]

It fails with

Error: could not read file /github/workspace/vendor/bundle/ruby/2.7.0/gems/jekyll-3.9.1/lib/site_template/_posts/0000-00-00-welcome-to-jekyll.markdown.erb: Invalid date '<%= Time.now.strftime('%Y-%m-%d %H:%M:%S %z') %>': Document 'vendor/bundle/ruby/2.7.0/gems/jekyll-3.9.1/lib/site_template/_posts/0000-00-00-welcome-to-jekyll.markdown.erb' does not have a valid date in the YAML front matter.

It does not seem to have anything to do with _config.yml.