Github Actions forked private repo not found

Hi,
I have forked my company’s private repository. I am trying to create an action that will lint the files when a PR is created from the organizations repo to the developers forked repo. Now in our actions settings for the organization repo we have enabled sharing tokens. But despite all that the action is still unable to find the forked repo.

This is what the action looks like.

name: PHP Code Linter
on: 
  pull_request_target:
     types: [assigned, opened, synchronize, reopened, edited]

jobs: 
  lint-php-code:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        php-versions: ['8.0']
    steps:
    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
        ref: ${{github.event.pull_request.head.ref}}
        repository: ${{github.event.pull_request.head.repo.full_name}}
        token: ${{ secrets.GITHUB_TOKEN }}

... code to run PHP linter