Update sbt-scalajs, scalajs-compiler, ... to 1.13.0 (#454)

Author: scala-steward

project/plugins.sbt

@@ -1,7 +1,7 @@
 addSbtPlugin("com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings"              % "3.0.2")
 addSbtPlugin("com.github.sbt"                    % "sbt-ci-release"                % "1.5.11")
 addSbtPlugin("com.typesafe"                      % "sbt-mima-plugin"               % "1.1.1")
-addSbtPlugin("org.scala-js"                      % "sbt-scalajs"                   % "1.12.0")
+addSbtPlugin("org.scala-js"                      % "sbt-scalajs"                   % "1.13.0")
 addSbtPlugin("org.portable-scala"                % "sbt-scalajs-crossproject"      % "1.2.0")
 addSbtPlugin("org.scala-native"                  % "sbt-scala-native"              % "0.4.10")
 addSbtPlugin("org.portable-scala"                % "sbt-scala-native-crossproject" % "1.2.0")