Be more specific with the Redis version being used

roles/matrix-redis/defaults/main.yml

@@ -5,8 +5,7 @@ matrix_redis_connection_password: ""
 matrix_redis_base_path: "{{ matrix_base_data_path }}/redis"
 matrix_redis_data_path: "{{ matrix_redis_base_path }}/data"
 
-matrix_redis_docker_image_v5: "redis:5.0-alpine"
-matrix_redis_docker_image_v6: "redis:6.0-alpine"
+matrix_redis_docker_image_v6: "docker.io/redis:6.0.10-alpine"
 matrix_redis_docker_image_latest: "{{ matrix_redis_docker_image_v6 }}"
 matrix_redis_docker_image_to_use: '{{ matrix_redis_docker_image_latest }}'