Announcing async-std v1.5.0

Hi all, we're back with a new release this year, this time containing some convenient quality-of-life improvements to async-std. This includes a few new trait bounds, and some welcome performance improvements for several of our production users.

We also recently crossed the 100.000 downloads mark on, which has really been a milestone for us. Thanks to everyone who has provided feedback, contributed, and tried async-std. Here's to the next 100.000!