chore(deps): update tornado requirement from <7,>=6 to >=6.5.6,<7

Updates the requirements on [tornado](https://github.com/tornadoweb/tornado) to permit the latest version.
- [Changelog](https://github.com/tornadoweb/tornado/blob/master/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.0.0...v6.5.6)

---
updated-dependencies:
- dependency-name: tornado
  dependency-version: 6.5.5
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements/adapter.txt

@@ -26,7 +26,7 @@ sanic>=25.3.0,<26; python_version>"3.8"
 
 starlette>=0.19.1,<0.45; python_version<"3.9"
 starlette>=0.49.3,<1; python_version>="3.9"
-tornado>=6,<7
+tornado>=6.5.6,<7
 uvicorn<1                                # The oldest version can vary among Python runtime versions
 gunicorn>=23.0.0,<24
 websocket_client>=1.2.3,<2               # Socket Mode 3rd party implementation