Revert "Gradle: Bump org.springframework.boot from 2.4.5 to 2.5.0"

There is a regression reported in [1] (also reported in Spring
Boot 2.4.6), preventing from leveraging a /config folder.

This reverts commit 9f3a6d5.

[1] spring-projects/spring-boot#26627

build.gradle.kts

@@ -16,7 +16,7 @@ plugins {
 
   id("com.diffplug.spotless") version "5.12.5"
 
-  id("org.springframework.boot") version "2.5.0" apply false
+  id("org.springframework.boot") version "2.4.5" apply false
   id("io.spring.dependency-management") version "1.0.11.RELEASE" apply false
 
   id("org.openapi.generator") version "5.1.1" apply false