Bump zod-openapi from 2.13.0 to 2.18.0

Bumps [zod-openapi](https://github.com/samchungy/zod-openapi) from 2.13.0 to 2.18.0.
- [Release notes](https://github.com/samchungy/zod-openapi/releases)
- [Commits](samchungy/zod-openapi@v2.13.0...v2.18.0)

---
updated-dependencies:
- dependency-name: zod-openapi
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

package.json

@@ -38,7 +38,7 @@
     "@typescript-eslint/rule-tester": "7.0.2",
     "skuba": "7.4.1",
     "zod": "3.23.8",
-    "zod-openapi": "2.13.0"
+    "zod-openapi": "2.18.0"
   },
   "packageManager": "pnpm@8.15.1",
   "engines": {