fix: samples/client/petstore/java/microprofile-rest-client-with-useSingleRequestParameter/pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-COMFASTERXMLJACKSONCORE-15907551

Author: snyk-bot

samples/client/petstore/java/microprofile-rest-client-with-useSingleRequestParameter/pom.xml

@@ -4,7 +4,7 @@
   <artifactId>microprofile-rest-client</artifactId>
   <packaging>jar</packaging>
   <name>microprofile-rest-client</name>
-  <description>This is a sample server Petstore server. For this sample, you can use the api key &#x60;special-key&#x60; to test the authorization filters.</description>
+  <description>This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.</description>
   <version>1.0.0</version>
   <build>
     <sourceDirectory>src/main/java</sourceDirectory>
@@ -157,7 +157,7 @@
     <junit.version>5.10.2</junit.version>
     <logback.version>1.5.13</logback.version>
     <cxf.version>3.2.7</cxf.version>
-    <jackson.jaxrs.version>2.17.1</jackson.jaxrs.version>
+    <jackson.jaxrs.version>2.21.2</jackson.jaxrs.version>
     <jakarta.activation.version>2.1.0</jakarta.activation.version>
     <jakarta.annotation.version>2.0.0</jakarta.annotation.version>
     <jakarta.json.bind.version>3.0.0</jakarta.json.bind.version>