Handle rate limits with pygithub using decorator

[mendhak]

In this PR I'm adding the ability to handle Github rate limits.

Using a decorator to capture the RateLimitException.
Then, calling the get_rate_limit() endpoint to get the actual limit.
Then, a thread.sleep to wait until the rate limit has been reset.

The best way I could think of was to wrap pygithub method calls.
I don't know of a cleaner way to do this without giving up intellisense/autocomplete.

Issue #42

[stv0g]

Hi @mendhak,

thanks for your PR!

I agree that this isnt the most elegant way to implement it.
I would prefer if we can do this directly within PyGitHub.

It should be much easiert to do there.

[mendhak]

Yeah sadly looks like PyGithub is happy to only provide information about the rate limits, but I can't find anything where they are handling the rate-limit-retry themselves. If you (anyone) can find anything, that would be quite useful, or point me at a neater approach of doing this.

I had a look at various threads:

PyGithub/PyGithub#1319
PyGithub/PyGithub#553

Also I had a look through their source code but that just seems to confirm, there are methods to return the value but not actually retry.