deps(example): bump the dependencies group

Bumps the dependencies group in /examples/nextjs-openai with 4 updates: [@ai-sdk/openai](https://github.com/vercel/ai), [ai](https://github.com/vercel/ai), [@types/react](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react) and [postcss](https://github.com/postcss/postcss).


Updates `@ai-sdk/openai` from 1.0.18 to 1.0.19
- [Release notes](https://github.com/vercel/ai/releases)
- [Changelog](https://github.com/vercel/ai/blob/main/CHANGELOG.md)
- [Commits](https://github.com/vercel/ai/compare/@ai-sdk/[email protected]...@ai-sdk/[email protected])

Updates `ai` from 4.0.34 to 4.0.36
- [Release notes](https://github.com/vercel/ai/releases)
- [Changelog](https://github.com/vercel/ai/blob/main/CHANGELOG.md)
- [Commits](https://github.com/vercel/ai/compare/[email protected]@4.0.36)

Updates `@types/react` from 19.0.6 to 19.0.7
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/react)

Updates `postcss` from 8.5.0 to 8.5.1
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.0...8.5.1)

---
updated-dependencies:
- dependency-name: "@ai-sdk/openai"
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
- dependency-name: ai
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
- dependency-name: "@types/react"
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dependencies
- dependency-name: postcss
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dependencies
...

Signed-off-by: dependabot[bot] <[email protected]>

examples/nextjs-openai/package.json

@@ -9,9 +9,9 @@
     "lint": "next lint"
   },
   "dependencies": {
-    "@ai-sdk/openai": "^1.0.18",
+    "@ai-sdk/openai": "^1.0.19",
     "@arcjet/next": "file:../../arcjet-next",
-    "ai": "^4.0.34",
+    "ai": "^4.0.36",
     "next": "15.1.4",
     "openai": "^4.78.1",
     "openai-chat-tokens": "^0.2.8",