Start building against Micrometer 1.12.9 snapshots

See gh-33325

Author: snicoll

framework-platform/framework-platform.gradle

@@ -8,7 +8,7 @@ javaPlatform {
 
 dependencies {
 	api(platform("com.fasterxml.jackson:jackson-bom:2.15.4"))
-	api(platform("io.micrometer:micrometer-bom:1.12.8"))
+	api(platform("io.micrometer:micrometer-bom:1.12.9-SNAPSHOT"))
 	api(platform("io.netty:netty-bom:4.1.111.Final"))
 	api(platform("io.netty:netty5-bom:5.0.0.Alpha5"))
 	api(platform("io.projectreactor:reactor-bom:2023.0.8"))