build(deps): bump tornado from 6.4.2 to 6.5.1 in /hack/mkdocs/image (#3815)

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
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

hack/mkdocs/image/requirements.txt

@@ -20,4 +20,4 @@ pymdown-extensions==10.14.3
 PyYAML==6.0.2
 six==1.17.0
 tabulate==0.9.0
-tornado==6.4.2
+tornado==6.5.1