fix: Sort contributors case insensitive (#1015)

when generating Northstar release notes

src-tauri/src/github/mod.rs

@@ -279,7 +279,7 @@ pub fn compare_tags_northstar(first_tag: Tag, second_tag: Tag) -> Result<String,
 
     // Convert the set to a sorted vector.
     let mut sorted_vec: Vec<String> = authors_set.into_iter().collect();
-    sorted_vec.sort();
+    sorted_vec.sort_by_key(|a| a.to_lowercase());
 
     // Define a string to prepend to each element.
     let prefix = "@";