Merge pull request #38 from APSL/dependabot/pip/docs/tornado-6.4.2

Bump tornado from 6.3.3 to 6.4.2 in /docs

Author: sastred

docs/requirements.txt

@@ -24,5 +24,5 @@ sphinxcontrib-jquery==4.1
 sphinxcontrib-jsmath==1.0.1
 sphinxcontrib-qthelp==1.0.6
 sphinxcontrib-serializinghtml==1.1.9
-tornado==6.3.3
+tornado==6.4.2
 urllib3==2.2.2