Merge pull request #1721 from nginx-proxy/dependabot/pip/test/requirements/backoff-1.11.1

chore(deps): bump backoff from 1.10.0 to 1.11.1 in /test/requirements

test/requirements/python-requirements.txt

@@ -1,4 +1,4 @@
-backoff==1.10.0
+backoff==1.11.1
 docker-compose==1.28.5
 docker==4.4.4
 pytest==6.2.2