feat(remote): retry on TooManyRequests

[aslafy-z]

Add HTTP 429 TooManyRequests to the list of retryable status codes.

[imjasonh]

As previously commented at #1628 (comment)

Retrying in the event of rate limits is a complex subject, and automatically retrying here can make problems worse instead of better.

If we go ahead with #1635 (which mostly seems fine) and you pass in 429 as a retryable code, that seems fine to me, but I wouldn't want to make this the new behavior for every dependency of this code.

But to Jon's comment in #1628 (comment) I wonder if you might be better off just passing in WithTransport and having complete control over the retry behavior yourself, without having to add a new option.

If you've tried that and it was insufficient or painful in some way, that would be helpful for motivating this change.

[aslafy-z]

@imjasonh I agree, this change can break things in some setups. I'd prefer to reuse the pre-configured Transport you go-containerregistry provides with all the retry behaviors. Let's close this PR and go ahead with #1635.