Aiohttp-spyne

What's Changed

* Require aiohttp 3.9.x
* Require python 3.8.x (drop support for 3.7)

* Officially support Python 3.11 (though previous releases already worked with it just fine)
* Improve cache to work correctly even if source address works (separate WSDL cache entry for each address).
* Cache locking to prevent pointless CPU load when cache is not yet warmed up, but there is a lot of simultaneous wsdl fetches
* Zeep usage cleanups in tests and examples
* Some typing cleanups
* Move all unit-tests to pytest and fixtures. This speeds up the tests nicely.

This is a small maintenance release. No code changes, just tooling.

* Move to poetry for package management
* Update development tools
* Add py.typed file so that type checkers (mypy) can find out typing information
* Change README to markdown

* Require aiohttp 3.7.0 or later
* Require spyne 2.14.0 or later (due to incompatible changes in spyne) and use the new InterfaceDocuments class (thanks WoolenSweater)
* Drop travis, and switch to github actions. This allows us to test all python versions (3.7 - 3.10).

* Use asyncio.run() in test soap client
* Bump test packages
* Validate against python 3.10, and make sure proper classifiers are set for it.

* Allow disabling of WSDL cache
* Move to travis-ci.com from .org
* Minor tweaks and corrections