Add missing content_type kwarg

[ahuang11]

Summary

Adds content_type to cloud_storage_upload_blob_from_file.

It's placed in the middle of the existing kwargs to match cloud_storage_upload_blob_from_string ordering.

Not sure if I should additionally add **upload_kwargs for other keywords missing?

Relevant Issue(s)

Closes #46

Checklist

• Summarized PR's changes in CHANGELOG.md

[desertaxle]

I agree it'd be worth while to add **kwargs to allow users to use other args that are offered. Also, this might be a good change to switch to using run_sync_in_worker_thread.

[ahuang11]

I have the run_sync_in_worker_thread in another incoming PR:
#41

[desertaxle]

Can you add **upload_kwargs to catch other arguments that we haven't specifically called out?