Replace with official Valkey image (#234)

* replace with official image

* use `7-alpine` tag

* prevent collision with other volumes

* Revert editing README formatting

---------

Co-authored-by: Émilien (perso) <4016501+unixfox@users.noreply.github.com>

docker-compose.yaml

@@ -25,13 +25,13 @@ services:
 
   redis:
     container_name: redis
-    image: cgr.dev/chainguard/valkey:latest
-    command: --save 30 1 --loglevel warning
+    image: docker.io/valkey/valkey:7-alpine
+    command: valkey-server --save 30 1 --loglevel warning
     restart: unless-stopped
     networks:
       - searxng
     volumes:
-      - valkey-data:/data
+      - valkey-data2:/data
     cap_drop:
       - ALL
     cap_add:
@@ -74,4 +74,4 @@ networks:
 volumes:
   caddy-data:
   caddy-config:
-  valkey-data:
+  valkey-data2: