Added the required image for README.
Added the required image for README.

hazelcast/hazelcast-simulator,hazelcast/hazelcast-simulator,pveentjer/hazelcast-simulator,Donnerbart/hazelcast-simulator,jerrinot/hazelcast-stabilizer,jerrinot/hazelcast-stabilizer,hazelcast/hazelcast-simulator,pveentjer/hazelcast-simulator,Donnerbart/hazelcast-simulator