build(deps): bump tornado from 6.4 to 6.4.1

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.4 to 6.4.1.
- [Changelog](https://github.com/tornadoweb/tornado/blob/master/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.4.0...v6.4.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -18,4 +18,4 @@ six==1.16.0
 urllib3==1.26.18
 websocket-client==1.3.1
 ply==3.11
-tornado==6.4
+tornado==6.4.1