added the missing prepare

plugins/modules/target.py

@@ -23,6 +23,9 @@ class Module(SystemdUnitModule):
         ),
     )
 
+    def prepare(self):
+        self.unitfile = (SYSTEMD_SERVICE_CONFIG, self.get("name")).with_stem(".target")
+
     def header(self) -> str:
         section = super().header()
         section += "AllowIsolate={}".format(systemdbool(self.get("allow_isolate", False)))