update plugins and nix after merge

Author: lemastero

project/build.properties

@@ -1 +1 @@
-sbt.version = 1.2.8
+sbt.version = 1.3.13

project/plugins.sbt

@@ -1,9 +1,9 @@
 logLevel := sbt.Level.Warn
-addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.5.1")
+addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.6.1")
 addSbtPlugin("org.scalastyle" %% "scalastyle-sbt-plugin" % "1.0.0")
 addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.7.5")
-addSbtPlugin("com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings" % "2.1.0")
+addSbtPlugin("com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings" % "3.0.0")
 addSbtPlugin("com.thesamet" % "sbt-protoc" % "0.99.25")
-addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.4.2")
+addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.5.1")
 
 libraryDependencies += "com.trueaccord.scalapb" %% "compilerplugin" % "0.6.6"