Bump junit from 4.12 to 4.13

Bumps [junit](https://github.com/junit-team/junit4) from 4.12 to 4.13.
- [Release notes](https://github.com/junit-team/junit4/releases)
- [Changelog](https://github.com/junit-team/junit4/blob/master/doc/ReleaseNotes4.12.md)
- [Commits](junit-team/junit4@r4.12...r4.13)

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

Author: dependabot-preview[bot]

build.gradle

@@ -53,7 +53,7 @@ dependencies {
     compile group: 'com.google.guava', name: 'guava', version: '23.0'
     compile group: 'org.apache.commons', name: 'commons-lang3', version: '3.9'
 
-    testCompile group: 'junit', name: 'junit', version: '4.12'
+    testCompile group: 'junit', name: 'junit', version: '4.13'
     testCompile group: 'org.hamcrest', name: 'hamcrest-library', version: '2.1'
     testCompile group: 'org.skyscreamer', name: 'jsonassert', version: '1.5.0'
     testCompile group: 'cd.go.plugin', name: 'go-plugin-api', version: project.pluginDesc.goCdVersion