feat: support passing of composer_auth to the workflow and environment

Author: imorland

.github/workflows/REUSABLE_backend.yml

@@ -45,9 +45,15 @@ on:
         required: false
         default: error_reporting=E_ALL
 
+    secrets:
+      composer_auth:
+        description: The Composer auth tokens to use for private packages.
+        required: false
+
 env:
   COMPOSER_ROOT_VERSION: dev-main
   FLARUM_TEST_TMP_DIR_LOCAL: tests/integration/tmp
+  COMPOSER_AUTH: ${{ secrets.composer_auth }}
 
 jobs:
   test:

.github/workflows/REUSABLE_frontend.yml

@@ -90,11 +90,15 @@ on:
       bundlewatch_github_token:
         description: The GitHub token to use for Bundlewatch.
         required: false
+      composer_auth:
+        description: The Composer auth tokens to use for private packages.
+        required: false
 
 env:
   COMPOSER_ROOT_VERSION: dev-main
   ci_script: ${{ inputs.js_package_manager == 'yarn' && 'yarn install --immutable' || 'npm ci' }}
   cache_dependency_path: ${{ inputs.cache_dependency_path || format(inputs.js_package_manager == 'yarn' && '{0}/yarn.lock' || '{0}/package-lock.json', inputs.frontend_directory) }}
+  COMPOSER_AUTH: ${{ secrets.composer_auth }}
 
 jobs:
   build: