Upgrade to testcontainers 1.21.0

Author: bclozel

platform/build.gradle

@@ -20,7 +20,7 @@ dependencies {
 	api(platform("org.jetbrains.kotlinx:kotlinx-coroutines-bom:1.8.1"))
 	api(platform("org.junit:junit-bom:5.12.2"))
 	api(platform("org.mockito:mockito-bom:5.16.0"))
-	api(platform("org.testcontainers:testcontainers-bom:1.20.6"))
+	api(platform("org.testcontainers:testcontainers-bom:1.21.0"))
 	api(platform("org.apache.logging.log4j:log4j-bom:2.24.3"))
 
 	constraints {