chetter-app-0.1.0

The changes in this release are all to support deleting 50+ references
when handling a "Closed PR" webhook event.

- Change reference namespace from ref/chetter/ to refs/heads/.  This was
  required in order to make use of GraphQL so that we can delete a large
  number of references in a single API call.  See:
  https://github.com/orgs/community/discussions/83980
- Drop RepositoryController::delete_ref in favor of
  RepositoryController::delete_refs.
- When handling a PR being closed, delete references in a background
  job.  Given how long it takes GitHub's API to delete a reference, it's
  not tenable to do this in the foreground where GitHub's webhook sender
  will just hang up.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "chetter-app"
-version = "0.0.3"
+version = "0.1.0"
 edition = "2021"
 
 [dependencies]