Configure using the `with` parameter

Configuration should be done using the with parameter instead of having to create a separate YAML file. We can still keep support for the YAML file as not to cause breaking changes for people who use the master version of this Action, or we could create a ticket in the repo to give users a heads up.

[TimonVS]

name: PR Labeler
on:
  pull_request:
    types: [opened]

jobs:
  pr-labeler:
    runs-on: ubuntu-latest
    steps:
      - uses: TimonVS/pr-labeler-action@master
        with:
          feature: ['feature/*', 'feat/*']
          fix: fix/*
          chore: chore/*
          fixed-branch: fixed-branch-name
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

In the above example each parameter provided to the with parameter will be exposed as an environment variable prefixed with INPUT_ (see https://help.github.com/en/articles/workflow-syntax-for-github-actions#jobsjob_idstepswith). So we can filter process.env to only include environment variables that are prefixed with INPUT_ and we have our config. The only downside is that an environment variable is always a string. So the array in the above example has to be evalled and another list syntax won’t work. The huge benefit is that configuration can be done right within the workflow instead of having to create a separate YAML file.

[asbjornu]

GITHUB_TOKEN can also preferably be passed in the with section, so env can be removed completely.