fix(deps): update dependency @backstage/plugin-scaffolder-backend to v3

Author: renovate[bot]

backstage/packages/backend/package.json

@@ -30,7 +30,7 @@
     "@backstage/plugin-permission-common": "^0.9.0",
     "@backstage/plugin-permission-node": "^0.10.0",
     "@backstage/plugin-proxy-backend": "^0.6.0",
-    "@backstage/plugin-scaffolder-backend": "^2.0.0",
+    "@backstage/plugin-scaffolder-backend": "^3.0.0",
     "@backstage/plugin-search-backend": "^2.0.0",
     "@backstage/plugin-search-backend-module-pg": "^0.5.41",
     "@backstage/plugin-search-backend-node": "^1.3.8",