fix(deps): update dependency org.junit:junit-bom to v5.12.0

Author: renovate[bot]

buildSrc/src/main/kotlin/otel.java-conventions.gradle.kts

@@ -135,7 +135,7 @@ testing {
     dependencies {
       implementation(project(project.path))
 
-      implementation(enforcedPlatform("org.junit:junit-bom:5.11.4"))
+      implementation(enforcedPlatform("org.junit:junit-bom:5.12.0"))
       implementation(enforcedPlatform("org.testcontainers:testcontainers-bom:1.20.5"))
       implementation(enforcedPlatform("com.google.guava:guava-bom:33.4.0-jre"))
       implementation(enforcedPlatform("com.linecorp.armeria:armeria-bom:1.31.3"))