Fix typo in the exception text

Fixes spring-atticgh-519
Closes spring-atticgh-561

Author: tmnuwan12

spring-cloud-aws-integration-test/src/test/java/org/springframework/cloud/aws/messaging/AbstractContainerTest.java

@@ -47,7 +47,7 @@ public void tearDown() throws Exception {
 			this.simpleMessageListenerContainer.stop(countDownLatch::countDown);
 
 			if (!countDownLatch.await(15, TimeUnit.SECONDS)) {
-				throw new Exception("Couldn't stop container withing 15 seconds");
+				throw new Exception("Couldn't stop container within 15 seconds");
 			}
 		}
 	}