fix: Fix runServer task when use spigot core

Fixes #55

Author: osipxd

src/main/kotlin/server/DevServerPlugin.kt

@@ -107,7 +107,7 @@ public class DevServerPlugin : Plugin<Project> {
             description = "Copy server core to server directory"
 
             val source = if (serverConfiguration.coreType == CoreType.SPIGOT) {
-                buildServerCore.map { it.buildToolsFile.get() }
+                buildServerCore.map { it.spigotFile.get() }
             } else {
                 downloadPaperclip.map { it.paperclipFile.get() }
             }

src/main/kotlin/server/task/BuildServerCore.kt

@@ -19,7 +19,7 @@ public abstract class BuildServerCore : JavaExec() {
     @get:Input
     public abstract val version: Property<String>
 
-    @OutputFile
+    @get:OutputFile
     public val spigotFile: Provider<File> = buildToolsFile.zip(version) { buildToolsFile, version ->
         File(buildToolsFile.parentFile, "spigot-$version.jar")
     }