Bump tornado from 6.4.2 to 6.5.1 in /images/federation-redirect

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.4.2 to 6.5.1.
- [Changelog](https://github.com/tornadoweb/tornado/blob/master/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.4.2...v6.5.1)

---
updated-dependencies:
- dependency-name: tornado
  dependency-version: 6.5.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

images/federation-redirect/requirements.txt

@@ -8,5 +8,5 @@ prometheus-client==0.14.1
     # via -r requirements.in
 pycurl==7.45.1
     # via -r requirements.in
-tornado==6.4.2
+tornado==6.5.1
     # via -r requirements.in