Stop handing Composer an empty GitHub token

The install step set github-oauth to ${{ secrets.COMPOSER_TOKEN }}, a secret
that was never created on any of these repositories. Composer therefore sent
an empty bearer token and GitHub rejected it — not just for wp-field-kit but
for every package, phpunit and phpcs included, which is why a build could
fail with "Could not authenticate against github.com" against nothing but
public dependencies.

The kit is public now, so no authentication is needed at all.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Tk8y5eZa3CHVVSM6nVxsJw

Author: arraypress

.github/workflows/ci.yml

@@ -28,12 +28,6 @@ jobs:
           tools: composer:v2
 
       - name: Install dependencies
-        # wp-field-kit is a private repository, so the checkout token is not
-        # enough — GITHUB_TOKEN is scoped to this repository alone. Set a PAT
-        # with repo:read as the COMPOSER_TOKEN secret, or make the kit public
-        # and drop this env block.
-        env:
-          COMPOSER_AUTH: '{"github-oauth":{"github.com":"${{ secrets.COMPOSER_TOKEN }}"}}'
         run: composer install --prefer-dist --no-progress --no-interaction
 
       - name: Lint