Overview

This small change upgrades FastAPI's internal dependency on Startlette to version 0.16.0, which incorporates several important bugfixes (see release notes for 0.15.0 and 0.16.0) that would be relevant for FastAPI users.

Testing done

• Run unit tests per the contribution docs
• Run a few examples from the FastAPI docs locally to ensure some "real-world" examples still work as expected

Other notes

• During the upgrade, there were only a couple of unit tests that failed due to upstream breakage relating to websocket connections, which were pretty straightforward to resolve
• It's worth noting that Starlette now requires AnyIO as of version 0.15.0; I don't claim to fully understand 100% of the reasons behind this switch, but from the commits I've read in Starlette, it seems to provide upstream support for different async runtimes (e.g. Trio) along with other nice async I/O primitives such as task groups

Apologies in advance if version upgrades aren't a typical part of outside contribution, but I figured this would be one way to get my feet wet!