Bump junit from 4.12 to 4.13.1 in /helloworlds/4.1-testing/mockito

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>

Author: dependabot[bot]

helloworlds/4.1-testing/mockito/pom.xml

@@ -15,7 +15,7 @@
 
     <properties>
         <java.version>1.7</java.version>
-        <junit.version>4.12</junit.version>
+        <junit.version>4.13.1</junit.version>
         <maven.compiler.version>3.3</maven.compiler.version>
         <mockito.version>1.9.5</mockito.version>
     </properties>