Add Python 3.11 to supported versions

[danielhuppmann]

Add Python 3.11 to supported versions

[danielhuppmann]

Ok, I have no idea why this PR is failing... Please help @meksor @phackstock @glatterf42!

[meksor]

My first guess: we might need the package python3.11-dev in the container used to run these checks.

[phackstock]

@meksor, seems like you're onto something aio-libs/aiohttp#6600 (comment).

[phackstock]

Installing python3.11-dev does not seem to be the solution... I'll keep on digging.

[phackstock]

@danielhuppmann, tests are finally running now.
After some painful debugging I was able to fix it.
The issue seems to have been a package called httptools which is a dependency of the uvicorn package.
uvicorn was pinned to an outdated version ^0.15, I now updated it to the closest version that fixed the install which turned out to be 0.17.

[phackstock]

Let's see if the tests run through. If they do I guess we can go ahead with the merge, fix the conda publishing and then release v0.3.1.

[phackstock]

Approving the PR since the tests are passing.