Specify stream type of Docker logs

[adamtheturtle]

This allows us to have code like:

    for line in container.logs(stream=True):
	line.decode() # Type checker knows that `line` is bytes

[github-actions[bot]]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[adamtheturtle]

@srittau @JelleZijlstra - sorry to bug but pinging just in case this was missed (among a group of PRs!). This is my first work with this kind of type, so any help is appreciated.

Thank you for all the hard work reviewing!

[github-actions[bot]]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[adamtheturtle]

Thank you @AlexWaygood for the review. I have applied your requested changes.

[github-actions[bot]]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉