Add support for debugging external artifacts (#262)

Closes #259

Author: ThadHouse

src/main/groovy/edu/wpi/first/gradlerio/frc/DebugInfoTask.groovy

@@ -9,6 +9,8 @@ import org.gradle.api.tasks.TaskAction
 @CompileStatic
 class DebugInfoTask extends DefaultTask {
 
+    List<Closure> extraArtifacts = []
+
     @TaskAction
     void writeDebugInfo() {
         def cfg = []
@@ -33,6 +35,10 @@ class DebugInfoTask extends DefaultTask {
                         language: "cpp"
                     ]
                 }
+            } else {
+                extraArtifacts.each { Closure toCall
+                    toCall(art, cfg)
+                }
             }
         }