container logs time precision

[fopinappb]

https://github.com/docker/docker-py/blob/master/docker/api/container.py#L845

This discards any microseconds from datetime while the API allows floats to be sent with the same precision as shown in the timestamps of the output (10^-9).

Even if datetime only keeps 10^-9, it'd still be nice to use that precision instead of just seconds.

moby/moby#41784 (comment)