Pydata-google-auth

- Default `use_local_webserver` to `True`. Google has deprecated the `use_local_webserver = False` ["out of band" (copy-paste) flow](https://developers.googleblog.com/2022/02/making-oauth-flows-safer.html?m=1#disallowed-oob>). The ``use_local_webserver = False`` option is planned to stop working in October 2022.

* Adds support for Python 3.10. (51)
* Fixes typo in documentation. (44)

* Adds pydata_google_auth.load_service_account_credentials() function to get service account credentials from the specified JSON path. (GH39)

- Mark package as 1.0, generally available.
- Update introduction with link to instructions on creating a Google Cloud
project. 18