Chore(deps): Bump tornado from 6.4.1 to 6.4.2

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.4.1 to 6.4.2.
- [Changelog](https://github.com/tornadoweb/tornado/blob/v6.4.2/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.4.1...v6.4.2)

---
updated-dependencies:
- dependency-name: tornado
  dependency-type: direct:production
...

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

requirements.txt

@@ -427,7 +427,7 @@ toml==0.10.2
     # via
     #   nibabies (pyproject.toml)
     #   sdcflows
-tornado==6.4.1
+tornado==6.4.2
     # via bokeh
 tqdm==4.66.5
     # via