Bump starlette from 0.21.0 to 0.23.1

Bumps [starlette](https://github.com/encode/starlette) from 0.21.0 to 0.23.1.
- [Release notes](https://github.com/encode/starlette/releases)
- [Changelog](https://github.com/encode/starlette/blob/master/docs/release-notes.md)
- [Commits](encode/starlette@0.21.0...0.23.1)

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

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

Author: dependabot[bot]

poetry.lock

@@ -91,7 +91,7 @@ sphinx-rtd-theme = "^0.5.2"
 strict-rfc3339 = "^0.7"
 webob = "*"
 mypy = "^0.971"
-starlette = "^0.21.0"
+starlette = "^0.23.1"
 httpx = "^0.23.3"
 
 [tool.pytest.ini_options]