Does not label PRs opened by non-contributors

[paularmstrong]

Problem: For any PR opened by someone that isn't a contributor of the repo, the action runs with no error, but does not label the PR.

Example: https://github.com/paularmstrong/build-tracker/runs/451006211?check_suite_focus=true

name: On pull request

on: pull_request

jobs:
  housekeeping:
    name: Housekeeping
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@master
      - name: Add labels
        uses: adamzolyak/monorepo-pr-labeler-action@patching
        env:
          BASE_DIRS: src|plugins|docs
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

[adamzolyak]

Thanks @paularmstrong! I'll take a look.

[paularmstrong]

Correction, contributor access is unrelated. It seems that it's an issue with PRs created from forks