tagged release

* Make challenge signing reusable

* bring back comment

* add type hinting

* add missing docstrings

* CI: fix deploy step

* WIP: refactor SigningKey class

* cleanup interface

* fix flake8

* flake8 ignore N818

* fix sign method return type in ifc

* refactor challenge formatting code

tagged release

* expand auth with scram helper; addd scram unit test
* remove autoapi generated rst sources
* more

* bump version; add missing yapf dependency

* fix upload of wstest reports

* fix and expand XBR IDL code generator
* fix wstest workflow (maybe;)

* fixes #1477
* update changelog
* update wstest
* add GH actions workflow for wstest

* 'traceback' is already formatted

* add debug / example code for full tracebacks

fix workaround in AB for a bug in twisted that by being fixed in tx 21.21, blows up the workaround (#1469)