update template (#5853)

Signed-off-by: Jess Frazelle <github@jessfraz.com>

rust/kcl-lib/tests/simtest.tmpl

@@ -8,9 +8,9 @@ mod TEST_NAME_HERE {
     }
 
     /// Test that parsing and unparsing KCL produces the original KCL input.
-    #[test]
-    fn unparse() {
-        super::unparse(TEST_NAME)
+    #[tokio::test(flavor = "multi_thread")]
+    async fn unparse() {
+        super::unparse(TEST_NAME).await
     }
 
     /// Test that KCL is executed correctly.