Allows user to specify grant_type in OAuthAuthenticator

[jj-nilbodee]

What

I'm trying to solve the issues where some of the connectors cannot migrate to use low-code CDK because it's using grant_type=client_credentials with OAuthAuthenticator

How

Allow users to be able to specify grant_type for OAuthAuthenticator while preserve the old behaviour by using a default value as refresh_token

Recommended reading order

1. x.java
2. y.python

🚨 User Impact 🚨

Are there any breaking changes? What is the end result perceived by the user? If yes, please merge this PR with the 🚨🚨 emoji so changelog authors can further highlight this if needed.

Pre-merge Checklist

Connector Generator

• Issue acceptance criteria met
• PR name follows PR naming conventions
• If adding a new generator, add it to the list of scaffold modules being tested
• The generator test modules (all connectors with -scaffold in their name) have been updated with the latest scaffold by running ./gradlew :airbyte-integrations:connector-templates:generator:testScaffoldTemplates then checking in your changes
• Documentation which references the generator is updated as needed

Tests

Unit

Put your unit tests output here.

Integration

Put your integration tests output here.

Acceptance

Put your acceptance tests output here.

[sherifnada]

Looks good! @jhajajaas could you add a test case in test_oauth.py and test_requests_native_auth.py to validate the grant_type is set properly?

Also, mind incrementing the version in setup.py with a minor version and adding a line in the changelog?