Fix the last issue raised by clippy nightly

I'm sorry about the noisy git history. I just hate force-pushing, as I
find it rude, you're just overrideing other people's history.

Once you publish it's for life.

Anyway, I'm not able these tests locally for now, so my only feedback is github
actions. And I've messed up in a363029 and missed this part.

I'll work in running these test in a container next time.

tests/test_value.rs

@@ -143,7 +143,7 @@ fn test_tagged() {
         Variant(usize),
     }
 
-    let value = serde_yaml_ng::to_value(&Enum::Variant(0)).unwrap();
+    let value = serde_yaml_ng::to_value(Enum::Variant(0)).unwrap();
 
     let deserialized: serde_yaml_ng::Value = serde_yaml_ng::from_value(value.clone()).unwrap();
     assert_eq!(value, deserialized);