chore: kafka dependency upgrade to address security vulnerability

Author: davetroiano

getting-started-with-ccloud-java/pom.xml

@@ -10,7 +10,7 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <kafka.client.version>3.7.1</kafka.client.version>
+    <kafka.client.version>4.0.0</kafka.client.version>
     <confluent.platform.version>5.5.0</confluent.platform.version>
     <maven.compiler.source>1.8</maven.compiler.source>
     <maven.compiler.target>1.8</maven.compiler.target>

scalable-payment-processing/pom.xml

@@ -32,8 +32,8 @@
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
         <exec-maven-plugin.version>1.2.1</exec-maven-plugin.version>
-        <kafka.scala.version>2.11</kafka.scala.version>
-        <kafka.version>2.3.0</kafka.version>
+        <kafka.scala.version>2.13</kafka.scala.version>
+        <kafka.version>2.8.2</kafka.version>
         <jersey.version>2.27</jersey.version>
         <jackson.version>2.9.6</jackson.version>
     </properties>