Update ryuk version to 0.8.1 (#8957)

Author: eddumelendez

core/src/main/java/org/testcontainers/utility/RyukContainer.java

@@ -9,7 +9,7 @@
 class RyukContainer extends GenericContainer<RyukContainer> {
 
     RyukContainer() {
-        super("testcontainers/ryuk:0.7.0");
+        super("testcontainers/ryuk:0.8.1");
         withExposedPorts(8080);
         withCreateContainerCmdModifier(cmd -> {
             cmd.withName("testcontainers-ryuk-" + DockerClientFactory.SESSION_ID);