await in deprecated get_attr

[dlashua]

This PR will prevent the error:

TypeError: argument of type 'coroutine' is not iterable

In the following code:

@time_trigger('startup')
def test():
    a = state.get_attr('sun.sun')

    for attrib in a:
        log.info(attrib)

[craigbarratt]

Oh no! I committed the sin of making a "simple" change without adding a test, and right before a release. Sigh.

[craigbarratt]

At least it will get people to use the new function...

[dlashua]

Haha. I wouldn't sweat it. It was time for me to start using getattr anyway. :) I had some "old" (relatively speaking, anyway) code that I hadn't worked on in a while. So I was surprised to see it start throwing errors. :)

[dadler]

FYI, this temporary breaking change just bit me too (in the 1.0.0 release). If the fix isn't released soon, I wonder if it'd be worth temporarily mentioning the bug in the reference documentation and release notes in HACS, which currently indicate get_attr is deprecated but works?