Remove option for non-callable `keys` argument to `incr_and_sum`

[LincolnPuzey]

The keys argument to incr_and_sum is always a callable when used internally by dramatiq.

dramatiq/dramatiq/rate_limits/backend.py

Lines 71 to 72 in 1b23e03

	keys(callable): A callable to return the list of keys to be
	summed over.

For backwards-compatibility it was still accepting a list in the implementations.

dramatiq/dramatiq/rate_limits/backends/stub.py

Lines 64 to 65 in 1b23e03

	# TODO: Drop non-callable keys in Dramatiq v2.
	key_list = keys() if callable(keys) else keys

dramatiq/dramatiq/rate_limits/backends/memcached.py

Lines 73 to 74 in 1b23e03

	# TODO: Drop non-callable keys in Dramatiq v2.
	key_list = keys() if callable(keys) else keys

dramatiq/dramatiq/rate_limits/backends/redis.py

Lines 85 to 86 in 1b23e03

	# TODO: Drop non-callable keys in Dramatiq v2.
	key_list = keys() if callable(keys) else keys

We should remove this option. Technically a breaking change, but I suspect not many users would be calling this method directly themselves

[udogri]

Hello, is this still open??

[LincolnPuzey]

@udogri Yes!