Bump tornado in /web in the pip group across 1 directory

Bumps the pip group with 1 update in the /web directory: [tornado](https://github.com/tornadoweb/tornado).


Updates `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
  dependency-group: pip
...

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

web/requirements.txt

@@ -25,6 +25,6 @@ sphinxcontrib-htmlhelp==2.0.0
 sphinxcontrib-jsmath==1.0.1
 sphinxcontrib-qthelp==1.0.3
 sphinxcontrib-serializinghtml==1.1.5
-tornado==6.4.1
+tornado==6.4.2
 urllib3==1.26.19
 breathe==4.33.1