Fix the client sometimes would not retry

[Pandede]

Resolves #108
After upgrading 2.9.0, sometimes the retry would not works as expected.
The temporary solution is downgrading to 2.8.3.

Root cause

This issue is inducted by the mechanism of checking whether skip the retry:

aiohttp_retry/aiohttp_retry/client.py

Lines 92 to 93 in 5ea8c8e

	if response.method not in self._retry_options.methods:
	return True

Sometimes, response.method is the string in lowercase (such as get) while self._retry_options.methods is a set of uppercase strings (such as {'GET', 'POST'}), the retry will be skipped, which does not match the expectation.

Solution

Ensure the method string is comparing in the same case.

[inyutin]

@Pandede cheers!