Rule proposal: no async in describe callback

[michielmulders]

According to this issue with Mocha (Describe block with async function behaving weirdly #2975),
it is not recommended to use the async keyword in the describe callback argument.

Example piece of code to avoid:

describe('yyy', async () => {

});

Preferred code:

describe('yyy', () => {

});

Would you like to consider this rule?
Thanks for your time!

[lo1tuma]

Yes, such a rule makes definitely sense. There is already a PR which implements this, see #188.

[lo1tuma]

Fixed by #188 and released in v5.3.0.