ci: update workflows

.github/workflows/backend.yml

@@ -0,0 +1,16 @@
+name: GB Redis Setup PHP
+
+on: [workflow_dispatch, push, pull_request]
+
+jobs:
+  run:
+    uses: flarum/framework/.github/workflows/REUSABLE_backend.yml@1.x
+    with:
+      enable_backend_testing: false
+      enable_phpstan: false
+      php_versions: '["7.4", "8.0", "8.1", "8.2", "8.3"]'
+
+      backend_directory: .
+
+    secrets:
+      composer_auth: '{"bearer":{"extiverse.com": "${{secrets.EXTIVERSE_COMPOSER_TOKEN}}"}}'