Remove (temporarily) unused plugin

Should be added back when setting up sbt-release

Author: alexarchambault

project/plugins.sbt

@@ -1,6 +1,5 @@
 addSbtPlugin("org.xerial.sbt" % "sbt-pack" % "0.8.0")
 addSbtPlugin("com.jsuereth" % "sbt-pgp" % "1.0.0")
-addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "1.1")
 addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.3.2")
 addSbtPlugin("io.get-coursier" % "sbt-coursier" % "1.0.0-M15")
 addSbtPlugin("com.dwijnand" % "sbt-travisci" % "1.1.0")