fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-7217828
- https://snyk.io/vuln/SNYK-PYTHON-TORNADO-7217829

requirements.txt

@@ -91,7 +91,7 @@ termcolor==1.1.0
 threadpoolctl==3.1.0
 toml==0.10.2
 tomli==2.0.1
-tornado==6.1
+tornado==6.4.1
 tqdm==4.64.0
 traitlets==5.2.2.post1
 typing_extensions==4.2.0