Upgrade spring-boot 3.0.6

- Also align framework 6.0.8 and security 6.0.3
- Relates #165

Author: jvalkeal

gradle.properties

@@ -1,7 +1,7 @@
 version=2.0.0-SNAPSHOT
-springBootVersion=3.0.3
-springFrameworkVersion=6.0.5
-springSecurityVersion=6.0.2
+springBootVersion=3.0.6
+springFrameworkVersion=6.0.8
+springSecurityVersion=6.0.3
 junitVersion=5.9.1
 mockitoVersion=4.8.1
 assertjVersion=3.23.1