[script] no need for GITHUB_TOKEN because sui is a public repo (Myste…

…nLabs#18544)

## Description 

Remove the Auth header because `sui` is a public repo..no need for
GTIHUB_TOKEN

## Test plan 

How did you test the new or updated feature?

---

## Release notes

Check each box that your changes affect. If none of the boxes relate to
your changes, release notes aren't required.

For each box you select, include information after the relevant heading
that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:

scripts/release_notes.py

@@ -124,7 +124,6 @@ def extract_notes_from_rebase_commit(commit):
     url = f"https://api.github.com/repos/MystenLabs/sui/commits/{commit}/pulls"
     headers = {
         "Accept": "application/vnd.github.v3+json",
-        "Authorization": f"token {os.environ['GITHUB_TOKEN']}",
     }
     req = urllib.request.Request(url, headers=headers)
     with urllib.request.urlopen(req) as response: