Use full requirement when serializing receipt (#5494)

## Summary

The current receipt doesn't capture quite enough information. For
example, it doesn't differentiate between editable and non-editable
requirements. This PR instead uses the full `Requirement` type. I think
we should use a custom representation like we do in the lockfile, but
I'm just using the default representation to demonstrate the idea.

crates/uv-git/src/git.rs

@@ -20,7 +20,9 @@ use crate::sha::GitOid;
 const CHECKOUT_READY_LOCK: &str = ".ok";
 
 /// A reference to commit or commit-ish.
-#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[derive(
+    Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, serde::Serialize, serde::Deserialize,
+)]
 pub enum GitReference {
     /// A specific branch.
     Branch(String),

crates/uv-git/src/sha.rs

@@ -26,7 +26,7 @@ impl From<GitOid> for GitSha {
     }
 }
 
-impl std::fmt::Display for GitSha {
+impl Display for GitSha {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "{}", self.0)
     }
@@ -40,6 +40,25 @@ impl FromStr for GitSha {
     }
 }
 
+impl serde::Serialize for GitSha {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        self.0.as_str().serialize(serializer)
+    }
+}
+
+impl<'de> serde::Deserialize<'de> for GitSha {
+    fn deserialize<D>(deserializer: D) -> Result<GitSha, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let value = String::deserialize(deserializer)?;
+        GitSha::from_str(&value).map_err(serde::de::Error::custom)
+    }
+}
+
 /// Unique identity of any Git object (commit, tree, blob, tag).
 ///
 /// Note this type does not validate whether the input is a valid hash.