drop 3.5 support

[mosquito]

No description provided.

[decaz]

@mosquito I guess that

aio-pika/aio_pika/exceptions.py

Lines 14 to 23 in 5af608d

	PAMQP_EXCEPTIONS = (pamqp.exceptions.PAMQPException,) + tuple(
	pamqp.specification.ERRORS.values(),
	)
	CONNECTION_EXCEPTIONS = (
	RuntimeError,
	ConnectionError,
	OSError,
	AMQPError,
	) + PAMQP_EXCEPTIONS

should be rewritten as the following:

CONNECTION_EXCEPTIONS = (
    RuntimeError,
    ConnectionError,
    OSError,
    AMQPError,
    pamqp.exceptions.PAMQPException,
)

[decaz]

I think ConnectionError can be removed because it inherits OSError which is already exists here.

[decaz]

In other files you are making import pamqp.commands, - I think it worth to do the same here so that it'll be the same everywhere.

[decaz]

@mosquito from pamqp's changelog: Changed pamqp.decode.timestamp to return a datetime.datetime instance instead of time.struct_time..

So I guess all helpers (encode_timestamp and decode_timestamp) can be removed, isn't it?