test(transport): adapt cancellation contract to Jackson 3

Author: loong10k

src/test/java/io/github/easy4j/hermes/transport/PublicCancellationContractTest.java

@@ -1,6 +1,6 @@
 package io.github.easy4j.hermes.transport;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
+import tools.jackson.databind.ObjectMapper;
 import io.github.easy4j.hermes.HermesHttpClientConfig;
 import io.github.easy4j.hermes.HermesOkHttpClientFactory;
 import io.github.easy4j.hermes.api.HermesHttpClient;