Merge pull request #1005 from searxng/dependabot/pip/master/redis-4.2.0

Bump redis from 4.1.4 to 4.2.0

requirements.txt

@@ -13,6 +13,6 @@ uvloop==0.16.0
 httpx-socks[asyncio]==0.7.2
 langdetect==1.0.9
 setproctitle==1.2.2
-redis==4.1.4
+redis==4.2.0
 mistletoe==0.8.2
 typing_extensions==4.1.1