evcc: Tesla API doesn't work any more

Describe the bug Tesla has deprecated the authentication endpoint that’s indirectly used via evcc.

To Reproduce Configure a vehicle with Tesla credentials and run evcc vehicle

Expected behavior I recieve a 400 Bad Request. No vehicle information is shown.

EVCC details: Show output of evcc -v:

./evcc --log trace vehicle
[main  ] INFO 2021/01/30 10:50:17 evcc 0.0.1-alpha (HEAD)
[main  ] INFO 2021/01/30 10:50:17 using config file /Users/michael/lab/evcc/evcc.yaml
[main  ] FATAL 2021/01/30 10:50:18 cannot create vehicle 'tesla': cannot create type 'tesla': 400 Bad Request

Executing the auth request agains the Tesla api returns 400 Bad Request and this response:

{
    "response": "endpoint_deprecated:_please_update_your_app."
}

The deprecation has been known for some time but now it seems the be gone. See: https://tesla-api.timdorr.com/api-basics/authentication

⚠ This information is out of date ⚠ Tesla has deprecated the /oauth/token endpoint in favor of using auth.tesla.com. I’m working on updating the documentation as soon as possible. Feel free to discuss this in issue 215.

More details here: https://github.com/timdorr/tesla-api/issues/215#issuecomment-770081554