⬆ upgrade spring boot to v3.4.0

Author: renovate[bot]

gradle/libs.versions.toml

@@ -15,7 +15,7 @@
 # java version is defined in my.jvm-base.gradle.kts
 # lib versions
 kotlin = "2.0.21"
-springBoot = "3.3.5"
+springBoot = "3.4.0"
 
 # plugin dep versions
 # empty for now