## Description 

When merging a PR, we can either use `squashed` or `rebase`.
Before, our release note script supports `squashed` commit only, this
change will add support to `rebase` PR as well.
The downside of this is it might take a bit longer to run given that
we'll need to send a HTTP request to Github API if it's not a squashed
commit. But given this script won't be run more than once a week, it's a
good tradeoff.

## Test plan 

`GITHUB_TOKEN=<my_PAT> python ./scripts/release_notes.py generate
9e2be6ad4185563ecd98bf35abfe92b86a0b280f
1428c71346045112c7adb1a316365c5cba325d9b`
(all the release notes from `releases/sui-v1.27.0-release` to
`releases/sui-v1.28.0-release` branch) now shows @bmwill 's
https://github.com/MystenLabs/sui/pull/18099

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## 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: