Bump tornado from 6.3.3 to 6.4.2 (#111)

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.3.3 to 6.4.2.
- [Changelog](https://github.com/tornadoweb/tornado/blob/v6.4.2/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.3.3...v6.4.2)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -118,7 +118,7 @@ tenacity==8.1.0
 terminado==0.17.0
 tinycss2==1.2.1
 tomli==2.0.1
-tornado==6.3.3
+tornado==6.4.2
 traitlets==5.5.0
 twine==4.0.1
 urllib3==1.26.12