fix: spring-kafka-example/pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGAPACHETOMCATEMBED-11799152
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-12008931

Author: snyk-bot

spring-kafka-example/pom.xml

@@ -20,7 +20,7 @@
 
 	<properties>
 		<java.version>21</java.version>
-		<spring.boot.version>3.5.4</spring.boot.version>
+		<spring.boot.version>3.5.5</spring.boot.version>
 		<spring.kafka.version>3.3.9</spring.kafka.version>
 		<lombok.version>1.18.38</lombok.version>
 		<jakarta.validation.version>3.1.1</jakarta.validation.version>