Fix deprecation warning

- Fixes #105

Author: gastaldi

src/main/kotlin/dev/jbang/idea/actions/SyncDependenciesAction.kt

@@ -2,6 +2,7 @@ package dev.jbang.idea.actions
 
 import com.intellij.notification.NotificationGroupManager
 import com.intellij.notification.NotificationType
+import com.intellij.openapi.actionSystem.ActionUpdateThread
 import com.intellij.openapi.actionSystem.AnAction
 import com.intellij.openapi.actionSystem.AnActionEvent
 import com.intellij.openapi.actionSystem.CommonDataKeys
@@ -88,6 +89,10 @@ class SyncDependenciesAction : AnAction() {
         }
     }
 
+    override fun getActionUpdateThread(): ActionUpdateThread {
+        return ActionUpdateThread.BGT
+    }
+
     private fun syncDependenciesBetweenJBangAndGradle(project: Project, module: Module, buildGradle: PsiFile, jbangScriptFile: PsiFile, moduleBuildGradle: Boolean) {
         var moduleName = module.name
         if (moduleName.contains('.')) {
@@ -385,4 +390,4 @@ class SyncDependenciesAction : AnAction() {
         val javaVersion = scriptText.lines().firstOrNull { it.startsWith("//JAVA ") }
         return javaVersion?.substring(6)?.trim() ?: "11"
     }
-}
+}