Update Release Notes Upload (#127)

# Update Release Notes Upload

## ♻️ Current situation & Problem
- Our release notes are not properly updated in App Store Connect. This
might be due to the issue noted in
fastlane/fastlane#18167.

## ⚙️ Release Notes 
- Tries to explicitly note the language in setting the release notes.

### Code of Conduct & Contributing Guidelines 

By submitting creating this pull request, you agree to follow our [Code
of
Conduct](https://github.com/StanfordBDHG/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/StanfordBDHG/.github/blob/main/CONTRIBUTING.md):
- [x] I agree to follow the [Code of
Conduct](https://github.com/StanfordBDHG/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/StanfordBDHG/.github/blob/main/CONTRIBUTING.md).

fastlane/Fastfile

@@ -180,7 +180,7 @@ platform :ios do
       deliver(
         app_identifier: appidentifier,
         release_notes: {
-          'default' => releasenotes
+          'en-US' => releasenotes
         },
         submit_for_review: true,
         force: true,