Upgrade testng in reactive-streams-tck

[barambani]

Currently reactive-streams-tck is bringing testng at version 7.0.0 that was using a jcommander version (com.beust:jcommander@1.72 ) affected by a security vulnerability

https://snyk.io/vuln/SNYK-JAVA-COMBEUST-174815

please consider updating it.

[lukaseder]

I'm running into this as well:

13:29:51,262 [ERROR] One or more dependencies were identified with vulnerabilities that have a CVSS score greater than or equal to '0.0':
13:29:51,268 [ERROR] bsh-2.0b4.jar: CVE-2016-2510
13:29:51,292 [ERROR] snakeyaml-1.6.jar: CVE-2017-18640

Is there a publication of a new version on the roadmap? 1.0.3 still has the dependency:
https://search.maven.org/artifact/org.reactivestreams/reactive-streams-tck