adjust to vmod_priv methods

Ref:
https://github.com/varnishcache/varnish-cache/commit/681c11998ec56dc4460a30585210f95a7850ea3b

src/vmod_tus.c

@@ -315,6 +315,12 @@ tus_task_free(void *ptr)
 	r->fcore = NULL;
 }
 
+static const struct vmod_priv_methods priv_task_methods[1] = {{
+		.magic = VMOD_PRIV_METHODS_MAGIC,
+		.type = "vmod_tus_priv_task",
+		.fini = tus_task_free
+}};
+
 struct tus_response *
 tus_task_new(VRT_CTX, struct VPFX(tus_server) *tussrv)
 {
@@ -340,7 +346,7 @@ tus_task_new(VRT_CTX, struct VPFX(tus_server) *tussrv)
 	}
 	INIT_OBJ(r, VMOD_TUS_RESPONSE_MAGIC);
 	task->priv = r;
-	task->free = tus_task_free;
+	task->methods = priv_task_methods;
 	return (r);
 }