Bump @backstage/plugin-auth-node from 0.4.17 to 0.6.15 in /backstage

Bumps [@backstage/plugin-auth-node](https://github.com/backstage/backstage/tree/HEAD/plugins/auth-node) from 0.4.17 to 0.6.15.
- [Release notes](https://github.com/backstage/backstage/releases)
- [Changelog](https://github.com/backstage/backstage/blob/master/plugins/auth-node/CHANGELOG.md)
- [Commits](https://github.com/backstage/backstage/commits/HEAD/plugins/auth-node)

---
updated-dependencies:
- dependency-name: "@backstage/plugin-auth-node"
  dependency-version: 0.6.15
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

backstage/packages/backend/package.json

@@ -23,7 +23,7 @@
     "@backstage/config": "^1.1.1",
     "@backstage/integration": "^1.9.0",
     "@backstage/plugin-auth-backend": "^0.22.3",
-    "@backstage/plugin-auth-node": "^0.4.1",
+    "@backstage/plugin-auth-node": "^0.6.15",
     "@backstage/plugin-catalog-backend": "^1.15.0",
     "@backstage/plugin-catalog-backend-module-github": "^0.6.0",
     "@backstage/plugin-catalog-backend-module-gitlab": "^0.3.4",