Bump tornado from 6.2 to 6.3.2 (#25)

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.2 to 6.3.2.
- [Changelog](https://github.com/tornadoweb/tornado/blob/master/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.2.0...v6.3.2)

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

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

requirements.txt

@@ -69,7 +69,7 @@ sphinxcontrib-jsmath==1.0.1
 sphinxcontrib-qthelp==1.0.3
 sphinxcontrib-serializinghtml==1.1.5
 tinycss2==1.2.1
-tornado==6.2
+tornado==6.3.2
 traitlets==5.9.0
 typing_extensions==4.5.0
 ukkonen==1.0.1