Merge pull request #2091 from CentreForDigitalHumanities/dependabot/pip/backend/tornado-6.5.7

Bump tornado from 6.5.6 to 6.5.7 in /backend

Author: lukavdplas

backend/requirements.txt

@@ -235,7 +235,7 @@ textdistance==4.6.3
     # via -r requirements.in
 threadpoolctl==3.6.0
     # via scikit-learn
-tornado==6.5.6
+tornado==6.5.7
     # via
     #   django-livereload-server
     #   flower