Bump junit from 4.12 to 4.13 (#4)

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>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

build.gradle

@@ -2,7 +2,7 @@ buildscript {
     ext {
         versions = [:]
         versions.guava = '13.0.1'
-        versions.junit = '4.12'
+        versions.junit = '4.13'
         versions.kotlin = '1.3.21'
         versions.lint = '22.2.0'
         versions.mockito = '1.9.5'