Bump jcommander from 1.78 to 1.81 (#187)

Bumps [jcommander](https://github.com/cbeust/jcommander) from 1.78 to 1.81.
- [Release notes](https://github.com/cbeust/jcommander/releases)
- [Changelog](https://github.com/cbeust/jcommander/blob/master/CHANGELOG.md)
- [Commits](cbeust/jcommander@1.78...1.81)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle

@@ -374,7 +374,7 @@ dependencies {
 
   compile 'aopalliance:aopalliance:1.0'
   compile "ch.qos.logback:logback-classic:${logbackRev}"
-  compile "com.beust:jcommander:1.78"
+  compile "com.beust:jcommander:1.81"
   compile "com.google.inject:guice:${guiceRev}"
   compile "com.google.inject.extensions:guice-assistedinject:${guiceRev}"
   compile "com.google.inject.extensions:guice-multibindings:${guiceRev}"