## Bug description

Creating a selector with an attribute isn't working at all.

`[data-attr="bla"]`

## Expected behavior

It should work

## How to reproduce

1. Create action
2. Add an attribute in the selector
3. 


## Additional context

The reason for this is that we store the attributes as `attr__data-attr` but we do not add `attr__` in the filtering. I am working on a solution.


#### *Thank you* for your bug report – we love squashing them!

posthog/models/event.py
parts: List[SelectorPart] = []
    def __init__(self, selector: str):
        self.parts = []
        tags = re.split(" ", selector)
        tags.reverse()
        for index, tag in enumerate(tags):
            if tag == ">":
                continue
            direct_descendant = False
            if index > 0 and tags[index - 1] == ">":
                direct_descendant = True
            part = SelectorPart(tag, direct_descendant)
            part.unique_order = len([p for p in self.parts if p.data == part.data])
            self.parts.append(copy.deepcopy(part))
class EventManager(models.QuerySet):
    def _element_subquery(self, selector: Selector) -> Tuple[Dict[str, Subquery], Dict[str, Union[F, bool]]]: