chore: use upstream redis for GitHub e2e tests (#234)

We are running Rekor end to end tests in Konflux testing our images and
stack. This change to the docker compose file should only affect GitHub
Actions e2e tests.

This partially reverts #159

//cc @Gregory-Pereira

Signed-off-by: Lance Ball <lball@redhat.com>

docker-compose.yml

@@ -31,7 +31,15 @@ services:
       retries: 3
       start_period: 10s
   redis-server:
-    image: registry.redhat.io/rhel9/redis-6@sha256:031a5a63611e1e6a9fec47492a32347417263b79ad3b63bcee72fc7d02d64c94
+    image: docker.io/redis:6.2
+    command: [
+      "--bind",
+      "0.0.0.0",
+      "--appendonly",
+      "yes",
+      "--requirepass",
+      "test"
+    ]
     ports:
       - "6379:6379"
     restart: always # keep the redis server running