Bump junit from 4.13.1 to 4.13.2 in /callbacks/maoni-slack

Bumps [junit](https://github.com/junit-team/junit4) from 4.13.1 to 4.13.2.
- [Release notes](https://github.com/junit-team/junit4/releases)
- [Changelog](https://github.com/junit-team/junit4/blob/main/doc/ReleaseNotes4.13.1.md)
- [Commits](junit-team/junit4@r4.13.1...r4.13.2)

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

callbacks/maoni-slack/build.gradle

@@ -65,7 +65,7 @@ dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
 
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    testImplementation 'junit:junit:4.13.1'
+    testImplementation 'junit:junit:4.13.2'
 
     implementation 'io.karn:khttp-android:0.1.2'
     implementation "org.jetbrains.anko:anko-sdk27:$anko_version"