Add target folder to gitignore.
Add target folder to gitignore.

non/sbt-plugins,markschaake/ai2-sbt-plugins,ryanai3/sbt-plugins,markschaake/ai2-sbt-plugins,jkinkead/sbt-plugins,jkinkead/sbt-plugins,non/sbt-plugins,allenai/sbt-plugins,ryanai3/sbt-plugins,ryanai3/sbt-plugins,jkinkead/sbt-plugins,markschaake/ai2-sbt-plugins