Update sbt-protoc to 1.0.8 (#559)

Author: scalameta-bot

project/plugins.sbt

@@ -4,7 +4,7 @@ addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.3.1")
 
 addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.13.1")
 
-addSbtPlugin("com.thesamet" % "sbt-protoc" % "1.0.7")
+addSbtPlugin("com.thesamet" % "sbt-protoc" % "1.0.8")
 
 addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.16.0")