Update all patch dependencies to v1.21.3 (#47)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

gradle/libs.versions.toml

@@ -4,7 +4,7 @@ jetbrains-annotations = "26.0.2"
 junit-jupiter = "5.10.2"
 logback = "1.5.18"
 mockito = "5.18.0"
-testcontainers = "1.21.2"
+testcontainers = "1.21.3"
 
 [libraries]
 hivemq-mqttClient = { module = "com.hivemq:hivemq-mqtt-client", version.ref = "hivemq-mqttClient" }