feat: allow sending non String payload with execute

[loispostula]

resolves #360

The approach I took is similar to the one outline here: #360 (comment)

Breaking changes

Drop of internal retry policy handler

Having to clone the request is a real challenge, as stated here: #360 (comment) and hyperium/tonic#733. I am in the opinion that such behaviour should not be inside of this library but in the client code, where they can use tools like tryhard to achieve reliable retry mechanism.

• the execute API has changed, so anyone using it outside of the crate might have to impact their code

[XAMPPRocky]

Thank you for your PR!

I am in the opinion that such behaviour should not be inside of this library but in the client code, where they can use tools like tryhard to achieve reliable retry mechanism.

I do not agree with this opinion, the octocrab client should be able of handling retries and throttling, just like the existing octokit client. I'm not going to merge a solution that removes this functionality. It may be a challenge but this is functionality that is worth preserving. If you're willing to make changes to this PR to support cloning streaming bodies, I'd be happy to merge it.

[loispostula]

@XAMPPRocky I' ve updated the pr to allow cloning the request by changng OctoBody<BoxBody> to OctoBody<Arc<RwLock<BoxBody>>>

[XAMPPRocky]

Thank you for your PR, and congrats on your first contribution! 🎉