Allow find tag by prefix hash

Author: Brooooooklyn

Diff for: src/repo.rs

@@ -1963,6 +1963,20 @@ impl Repository {
         }
     }
 
+    /// Lookup a tag object by prefix hash from the repository.
+    pub fn find_tag_by_prefix(&self, prefix_hash: &str) -> Result<Tag<'_>, Error> {
+        let mut raw = ptr::null_mut();
+        unsafe {
+            try_call!(raw::git_tag_lookup_prefix(
+                &mut raw,
+                self.raw,
+                Oid::from_str(prefix_hash)?.raw(),
+                prefix_hash.len()
+            ));
+            Ok(Binding::from_raw(raw))
+        }
+    }
+
     /// Delete an existing tag reference.
     ///
     /// The tag name will be checked for validity, see `tag` for some rules