Bump junit from 4.12 to 4.13.1 in /modules/reactive-streams

Bumps [junit](https://github.com/junit-team/junit4) from 4.12 to 4.13.1.
- [Release notes](https://github.com/junit-team/junit4/releases)
- [Changelog](https://github.com/junit-team/junit4/blob/main/doc/ReleaseNotes4.12.md)
- [Commits](junit-team/junit4@r4.12...r4.13.1)

Signed-off-by: dependabot[bot] <support@github.com>

modules/reactive-streams/pom.xml

@@ -142,7 +142,7 @@
  <scope>test</scope>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
- <version>4.12</version>
+ <version>4.13.1</version>
  </dependency>
 
  </dependencies>