Bump uvicorn from 0.18.3 to 0.19.0 (#2429)

Bumps [uvicorn](https://github.com/encode/uvicorn) from 0.18.3 to 0.19.0.
- [Release notes](https://github.com/encode/uvicorn/releases)
- [Changelog](https://github.com/encode/uvicorn/blob/master/CHANGELOG.md)
- [Commits](encode/uvicorn@0.18.3...0.19.0)

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

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Tom Christie <tom@tomchristie.com>

requirements.txt

@@ -36,4 +36,4 @@ pytest-trio==0.7.0
 trio==0.21.0
 trio-typing==0.7.0
 trustme==0.9.0
-uvicorn==0.18.3
+uvicorn==0.19.0