Allow reqwest 0.13's `rustls-no-provider` feature

[valkum]

The update to reqwest 0.13 causes some trouble if you want to rely on ring instead of aws-ls-rs.

See seanmonstar/reqwest#2924. You might also want to reach out here: seanmonstar/reqwest#2871

I am still not sure what the best way for libraries is with reqwest 0.13. Nevertheless, unless there is a better and documented recommendation, async-openai should offer a way to enable reqwest/rustls-no-provider instead of reqwest/rustls

[64bit]

PR is welcome!