Merge pull request #18 from vertical-blank/fix-plugins

fix plugins.sbt

Author: vertical-blank

project/plugins.sbt

@@ -3,4 +3,3 @@ addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "0.6.1")
 addSbtPlugin("org.xerial.sbt"     % "sbt-sonatype"             % "3.8.1")
 addSbtPlugin("com.github.gseitz"  % "sbt-release"              % "1.0.12")
 addSbtPlugin("com.jsuereth"       % "sbt-pgp"                  % "2.0.1")
-addSbtPlugin("org.xerial.sbt"     % "sbt-sonatype"             % "3.8")