Merge pull request #1347 from watchdogpolska/renovate/gunicorn-21.x

chore(deps): update dependency gunicorn to v21

requirements/production.txt

@@ -1,5 +1,5 @@
 # Pro-tip: Try not to put anything here. There should be no dependency in
 #	production that isn't in development.
 -r base.txt
-gunicorn==20.1.0
+gunicorn==21.2.0
 gevent==23.9.1