feat: support "core": null

[hirasso]

Adds support for explicitly setting "core" to null:

jobs:
  wp-env:
    runs-on: ubuntu-latest
    name: Setup WordPress Environment
    steps:
      - name: Start wp-env
        uses: godaddy-wordpress/setup-wp-env@v1
        with:
          core: 'null'

This is helpful to prevent tests from failing in CI as described here.

Note

In my tests, core: null (without quotes) was being converted to an empty string. Passing it as a string was my first idea that works, but there might be better ones.

Drive-By

print the resulting .wp-env.override.json for easier debugging:

Run jq . .wp-env.override.json
{
  "env": {},
  "core": null,
  "phpVersion": "8.2"
}