Dependencies with withSources confuse the plugin

[SethTisue]

so for example in Fortify I'm getting:

[error] Caused by: java.lang.RuntimeException: Multiple elements for the same key (com.lightbend,scala-st-nodes):
[error] 	ModuleInfo(com.lightbend,scala-st-nodes,0.0.0+105-e8ef584e,Some((Artifact(scala-st-nodes, src, jar, Some(sources), Vector(), Some(file://///Users/tisue/.ivy2//local/com.lightbend/scala-st-nodes/0.0.0+105-e8ef584e/srcs/scala-st-nodes-sources.jar), Map(), None, false),/Users/tisue/.ivy2/local/com.lightbend/scala-st-nodes/0.0.0+105-e8ef584e/srcs/scala-st-nodes-sources.jar)))
[error] 	ModuleInfo(com.lightbend,scala-st-nodes,0.0.0+105-e8ef584e,Some((Artifact(scala-st-nodes, jar, jar, Some(assembly), Vector(), Some(file://///Users/tisue/.ivy2//local/com.lightbend/scala-st-nodes/0.0.0+105-e8ef584e/jars/scala-st-nodes-assembly.jar), Map(), None, false),/Users/tisue/.ivy2/local/com.lightbend/scala-st-nodes/0.0.0+105-e8ef584e/jars/scala-st-nodes-assembly.jar)))

note that one of the "duplicates" is a source jar

the problem goes away if I remove withSources from the dependency:

 libraryDependencies +=
-  "com.lightbend" % "scala-st-nodes" % "0.0.0+105-e8ef584e" % "provided" classifier "assembly" withSources ()
+  "com.lightbend" % "scala-st-nodes" % "0.0.0+105-e8ef584e" % "provided" classifier "assembly"

[SethTisue]

@pvlugter this seems rather similar to #68, maybe it would be an easy fix for you since you've already been up in that code...?