Update dependency org.testcontainers:testcontainers-bom to v1.21.0 (#1319)

Author: nakamura-to

gradle/libs.versions.toml

@@ -19,7 +19,7 @@ junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine" }
 junit-platform-launcher = { module = "org.junit.platform:junit-platform-launcher" }
 apiguardian = { module = "org.apiguardian:apiguardian-api", version = "1.1.2" }
 
-testcontainers-bom = { module = "org.testcontainers:testcontainers-bom", version = "1.20.6" }
+testcontainers-bom = { module = "org.testcontainers:testcontainers-bom", version = "1.21.0" }
 testcontainers-mysql = { module = "org.testcontainers:mysql" }
 testcontainers-oracle = { module = "org.testcontainers:oracle-xe" }
 testcontainers-postgresql = { module = "org.testcontainers:postgresql" }