Stop using libs-release

This commit makes sure we narrow down dependencies of the Spring
Framework to only Maven central. Optional dependencies that are not
available on Maven Central are now served from a more specific
repository (`libs-spring-framework-build`).

Closes gh-23124

build.gradle

@@ -295,7 +295,7 @@ configure(allprojects) { project ->
 		}
 		repositories {
 			mavenCentral()
-			maven { url "https://repo.spring.io/libs-release" }
+			maven { url "https://repo.spring.io/libs-spring-framework-build" }
 			maven { url "https://repo.spring.io/milestone" } // Reactor
 			maven { url "https://repo.spring.io/snapshot" } // Reactor
 		}