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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Fixes: #455

requirements/basic.txt

@@ -1,3 +1,3 @@
 cartola>=0.18
 taskio==0.0.7
-tornado==6.4
+tornado==6.4.1