Update Spring Boot version to 3.5.9

Author: mofterdinger

pom.xml

@@ -17,7 +17,7 @@
 		<!-- DEPENDENCIES VERSION -->
 		<jdk.version>21</jdk.version>
 		<cds.services.version>4.6.1</cds.services.version>
-		<spring.boot.version>3.5.6</spring.boot.version>
+		<spring.boot.version>3.5.9</spring.boot.version>
 		<cf-java-logging-support.version>3.8.5</cf-java-logging-support.version>
 
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>