Fix gcloud command

[amrit110]

This pull request contains a minor update to the project version and an improvement to the authentication token fetching logic. The most important changes are listed below:

Version update:

• Updated the project version in pyproject.toml from 0.3.0 to 0.3.1 to reflect the new changes.

Authentication improvement:

• Modified the fetch_token_from_service function in src/aieng_platform_onboard/utils.py to include the --audiences flag with the gcloud auth print-identity-token command, improving token audience specification for authentication.