Bump sse-starlette from 1.5.0 to 1.6.1

Bumps [sse-starlette](https://github.com/sysid/sse-starlette) from 1.5.0 to 1.6.1.
- [Release notes](https://github.com/sysid/sse-starlette/releases)
- [Changelog](https://github.com/sysid/sse-starlette/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sysid/sse-starlette/compare/v1.5.0...v1.6.1)

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

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