build(deps): bump openapi-backend from 5.13.0 to 5.15.0 (#7077)

Bumps [openapi-backend](https://github.com/openapistack/openapi-backend) from 5.13.0 to 5.15.0.
- [Release notes](https://github.com/openapistack/openapi-backend/releases)
- [Commits](openapistack/openapi-backend@5.13.0...5.15.0)

---
updated-dependencies:
- dependency-name: openapi-backend
  dependency-version: 5.15.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pnpm-lock.yaml

@@ -57,7 +57,7 @@
     "measured-core": "^2.0.0",
     "mime-types": "^3.0.1",
     "oidc-provider": "^9.4.2",
-    "openapi-backend": "^5.13.0",
+    "openapi-backend": "^5.15.0",
     "proxy-addr": "^2.0.7",
     "rate-limiter-flexible": "^7.2.0",
     "rehype": "^13.0.2",