Bump starlette in /samples/server/petstore/python-fastapi

Bumps [starlette](https://github.com/Kludex/starlette) from 0.40.0 to 0.49.1.
- [Release notes](https://github.com/Kludex/starlette/releases)
- [Changelog](https://github.com/Kludex/starlette/blob/main/docs/release-notes.md)
- [Commits](Kludex/starlette@0.40.0...0.49.1)

---
updated-dependencies:
- dependency-name: starlette
  dependency-version: 0.49.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

samples/server/petstore/python-fastapi/requirements.txt

@@ -26,7 +26,7 @@ python-multipart==0.0.18
 PyYAML>=5.4.1,<6.1.0
 requests==2.32.4
 Rx==1.6.1
-starlette==0.40.0
+starlette==0.49.1
 typing-extensions==4.13.2
 ujson==4.0.2
 urllib3==2.5.0