BigQuery Anonymous Authentication

[kpolley]

Description

Adds the option to authenticate to BigQuery using anonymous credentials. Useful for public datasets and unit testing. Will help solve for #358

Checklist

• I have read the contributing guide and understand what's expected of me
• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• I have opened an issue to add/update docs, or docs changes are not required/relevant for this PR
• I have run changie new to create a changelog entry

[nssalian]

Thanks for opening the PR, @kpolley. The change looks good.
Do you think we could add a small unit test - in either conftest or test_bigquery_adapter?

[kpolley]

Thanks for opening the PR, @kpolley. The change looks good. Do you think we could add a small unit test - in either conftest or test_bigquery_adapter?

Added a unit test in test_bigquery_adapter. Let me know if there's anything else and feel free to modify the PR as well.

[github-actions]

This PR has been marked as Stale because it has been open with no activity as of late. If you would like the PR to remain open, please comment on the PR or else it will be closed in 7 days.

[github-actions]

Although we are closing this PR as stale, it can still be reopened to continue development. Just add a comment to notify the maintainers.