Update test containers to 1.21.4

The dummy junit code is no longer needed as testcontainers/testcontainers-java#970 has been fixed.

Author: jacomago

pom.xml

@@ -161,14 +161,8 @@
         <dependency>
             <groupId>org.testcontainers</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>1.19.3</version>
+            <version>1.21.4</version>
             <scope>test</scope>
-            <exclusions>
-                <exclusion>
-                    <groupId>junit</groupId>
-                    <artifactId>junit</artifactId>
-                </exclusion>
-            </exclusions>
         </dependency>
         <dependency>
             <groupId>io.netty</groupId> <!-- Need for running tests on mac -->