USPS requires POST method for OAUTH2 authorization

[ianbaek]

I wanted to integrate usps oauth, thus I added below in providers.yaml based on their doc. However, the issue is that 'https://api.usps.com/oauth2/v3/authorize' requires only POST method and it returns error. I understand standard oauth2 is GET to authorize. Is there a way to specify the method in providers.yaml?

usps:
categories:
- shipping
auth_mode: OAUTH2
authorization_url: https://api.usps.com/oauth2/v3/authorize
token_url: https://api.usps.com/oauth2/v3/token
token_request_auth_method: basic
authorization_params:
response_type: code
token_params:
grant_type: authorization_code
refresh_params:
token_type_hint: refresh_token
proxy:
base_url: https://api.usps.com

[linear]

NAN-1399 USPS requires POST method for OAUTH2 authorization