git-ref-format: fix to deserialization

When deserializing through `serde_json::from_value` the following
error would occur:

  panicked at 'called Result::unwrap() on an Err value: Error("invalid
  type: string "master", expected a borrowed string", line: 0, column:
  0)'

To fix this it is necessary for the Deserialize implementations to
deserialize into an owned String and convert from there.

While attempting to test this the `Qualified` and `Namespaced`
implementations were not able to be used:

  error: implementation of `serde::de::Deserialize` is not general enough
  --> git-ref-format/t/src/properties/name.rs:86:9
   |
86 |         roundtrip::json_value(qualified);
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `serde::de::Deserialize` is not general enough
   |
   = note: `Qualified<'_>` must implement `serde::de::Deserialize<'0>`, for any lifetime `'0`...
   = note: ...but `Qualified<'_>` actually implements
   `serde::de::Deserialize<'1>`, for some specific lifetime `'1`

The Deserialize for both of those types now return owned data by
returning a 'static lifetime instead.

Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett

git-ref-format/t/src/properties/pattern.rs

@@ -48,6 +48,11 @@ proptest! {
         roundtrip::json(refspec::PatternString::try_from(input).unwrap())
     }
 
+    #[test]
+    fn json_value(input in gen::with_glob()) {
+        roundtrip::json_value(refspec::PatternString::try_from(input).unwrap())
+    }
+
     #[test]
     fn cbor(input in gen::with_glob()) {
         roundtrip::cbor(refspec::PatternString::try_from(input).unwrap())