SigV4 support to push to AWS-based pushgateways?

AFAIU currently there's no handler in the library to handle push_to_gateway() calls to an AWS-based pushgateway which needs the access key, secret key and all that good stuff.

I saw this PR which adds such support to the Go client: https://github.com/prometheus/prometheus/pull/8509/files. Wondering if this will be supported by the Python client in the future?

Start at the Python client's push_to_gateway() entry point and compare it with the referenced Prometheus Go PR #8509 to understand the expected AWS SigV4 behavior. Done means the client can authenticate pushes to AWS-based pushgateways using the required credentials and the resulting behavior is verified.