Remove spring-build-src module from BOM

Issue: SPR-15932

Author: bclozel

spring-framework-bom/spring-framework-bom.gradle

@@ -20,7 +20,7 @@ install {
 				asNode().children().last() + {
 					delegate.dependencyManagement {
 						delegate.dependencies {
-							parent.subprojects.sort { "$it.name" }.each { p ->
+							parent.moduleProjects.sort { "$it.name" }.each { p ->
 								if (p != project) {
 									delegate.dependency {
 										delegate.groupId(p.group)